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46 - Databases Overview and Environment Setup/005 PostgreSQL Overview & Installation (including pgAdmin installation)_en.srt

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+1
+00:00:06,000 --> 00:00:10,000
+Hello, dissonance in previous lesson, we hold an overview of my sequel.
+
+2
+00:00:10,000 --> 00:00:17,000
+Also, we installed it on our laptops, but in this lesson, I would like to refuse you another popular
+
+3
+00:00:17,000 --> 00:00:21,000
+database management system that is called PostgreSQL.
+
+4
+00:00:22,000 --> 00:00:29,000
+We're going to study this lesson from general overview of PostgreSQL and its main features after you
+
+5
+00:00:29,000 --> 00:00:32,000
+become a little bit familiar to this relational database management system.
+
+6
+00:00:33,000 --> 00:00:35,000
+We'll proceed with practical cause of the lesson.
+
+7
+00:00:36,000 --> 00:00:43,000
+We're going to install is you progress SQL Server e.g. admin stack builder and come online tools.
+
+8
+00:00:43,000 --> 00:00:49,000
+The goal of our lesson is to make sure that your environment is ready for further learning of databases.
+
+9
+00:00:50,000 --> 00:00:54,000
+So I will explain you how to connect the database using Pidgey admin.
+
+10
+00:00:55,000 --> 00:01:00,000
+I'm going to show you how to create new connections to other PostgreSQL servers.
+
+11
+00:01:00,000 --> 00:01:01,000
+And then there was a lesson.
+
+12
+00:01:01,000 --> 00:01:06,000
+You will also understand how to manage progress SQL Windows service.
+
+13
+00:01:06,000 --> 00:01:08,000
+We have a lot of plans for this lesson.
+
+14
+00:01:08,000 --> 00:01:10,000
+Let's get it started.
+
+15
+00:01:11,000 --> 00:01:17,000
+PostgreSQL is a powerful open source object, relational database management system that uses and extends
+
+16
+00:01:17,000 --> 00:01:20,000
+the sequel then which combined with many features.
+
+17
+00:01:21,000 --> 00:01:25,000
+Let's safely store and skills the most complicated data workloads.
+
+18
+00:01:25,000 --> 00:01:33,000
+It's also worth dimensions of possibly a sequel has come a long way since 1986, when it was part of
+
+19
+00:01:33,000 --> 00:01:40,000
+the PostgreSQL project as the University of California at Berkeley and has more than 30 years of active
+
+20
+00:01:40,000 --> 00:01:42,000
+development on the core platform.
+
+21
+00:01:42,000 --> 00:01:48,000
+What a sequel is not controlled by any corporation or other private entity, and the source code is
+
+22
+00:01:48,000 --> 00:01:50,000
+available free of charge.
+
+23
+00:01:50,000 --> 00:01:57,000
+PostgreSQL is loved by many developers across all over the world because it has earned a strong reputation
+
+24
+00:01:57,000 --> 00:02:04,000
+for its proven architecture, reliability, data integrity, robust feature, set extensibility and
+
+25
+00:02:04,000 --> 00:02:10,000
+so dedication of the open source community behind the software to consistently deliver performant and
+
+26
+00:02:10,000 --> 00:02:11,000
+innovative solutions.
+
+27
+00:02:12,000 --> 00:02:16,000
+The sequel is cross-platform, and it runs on all major operating systems.
+
+28
+00:02:17,000 --> 00:02:24,000
+Also, it is Transaction's compliant since 2001, and this powerful add ons such as the popular post
+
+29
+00:02:24,000 --> 00:02:27,000
+use spatial database extender.
+
+30
+00:02:27,000 --> 00:02:33,000
+It is no surprise that possibly a sequel has become the open source relational database of choice for
+
+31
+00:02:33,000 --> 00:02:35,000
+many people and organizations.
+
+32
+00:02:35,000 --> 00:02:36,000
+It was great.
+
+33
+00:02:36,000 --> 00:02:43,000
+Sequel comes with many features aimed to help developers build applications administrators to protect
+
+34
+00:02:43,000 --> 00:02:49,000
+data integrity and build fault tolerant environments and help you manage your data no matter how big
+
+35
+00:02:49,000 --> 00:02:51,000
+or small the data set.
+
+36
+00:02:51,000 --> 00:02:58,000
+And on top of all things that we have already discussed about possible SQL, it is also highly extensible.
+
+37
+00:02:58,000 --> 00:03:00,000
+What does this mean?
+
+38
+00:03:00,000 --> 00:03:07,000
+For example, you can define your own data types, build out custom functions, even write code from
+
+39
+00:03:07,000 --> 00:03:11,000
+different programming languages without compiling your database.
+
+40
+00:03:11,000 --> 00:03:16,000
+Pretty cool features, don't you think so is a lesson about my school?
+
+41
+00:03:16,000 --> 00:03:23,000
+We also discussed on the high level existence standards for sequel structured query language, and also
+
+42
+00:03:23,000 --> 00:03:27,000
+we mention is that each database management system may have its own dialect.
+
+43
+00:03:28,000 --> 00:03:35,000
+Dialect includes some minor differences in syntax lack of the stated on the PostgreSQL Oracle website,
+
+44
+00:03:35,000 --> 00:03:42,000
+possibly a tries to conform with the school's standards where such conformance doesn't contradict traditional
+
+45
+00:03:42,000 --> 00:03:46,000
+features or could lead to pure architectural decisions.
+
+46
+00:03:47,000 --> 00:03:52,000
+Still, it is not always clear how syntax differences may impact on architectural decisions.
+
+47
+00:03:52,000 --> 00:03:54,000
+My subjective opinion?
+
+48
+00:03:54,000 --> 00:03:59,000
+This is just inheritance from times when there were no standards for school.
+
+49
+00:03:59,000 --> 00:04:06,000
+And as you already know, PostgreSQL is not a new project as a conclusion of dialogue differences.
+
+50
+00:04:06,000 --> 00:04:12,000
+I'd like to say that many of the features required by the school standards are supported, though sometimes
+
+51
+00:04:12,000 --> 00:04:15,000
+with slightly different syntax or function.
+
+52
+00:04:16,000 --> 00:04:18,000
+Let's review core features of a sequel.
+
+53
+00:04:19,000 --> 00:04:26,000
+Among the features, it is worse dimensions next one's data types, customizations, composite custom
+
+54
+00:04:26,000 --> 00:04:34,000
+types just in time compilation of expressions Sophisticated Keyword Planner Optimizer Index only scans
+
+55
+00:04:35,000 --> 00:04:45,000
+multi columns statistics advanced indexing point in time recovery active standbys replication asynchronous
+
+56
+00:04:45,000 --> 00:04:53,000
+synchronous logical right that log in syndication features multifactor authentication with certificates
+
+57
+00:04:54,000 --> 00:04:58,000
+and an additional massive support of procedural languages.
+
+58
+00:04:59,000 --> 00:05:07,000
+Sequel Jason Pass Expressions for data wrappers connect to other databases or streams was a standard
+
+59
+00:05:07,000 --> 00:05:14,000
+sequel interface many extensions that provide additional functionality, including Porzingis.
+
+60
+00:05:14,000 --> 00:05:18,000
+These are just some of the features that you can find in possibly a sequel.
+
+61
+00:05:19,000 --> 00:05:19,000
+Probably.
+
+62
+00:05:19,000 --> 00:05:24,000
+We can say that you already have an impression about PostgreSQL, and yes, you are right.
+
+63
+00:05:25,000 --> 00:05:27,000
+This is also called database management system.
+
+64
+00:05:28,000 --> 00:05:34,000
+This is one of the reasons why it's become popular, so let's now install it on our computers.
+
+65
+00:05:35,000 --> 00:05:40,000
+The first thing that we need to do is to download distribution back for your operating system.
+
+66
+00:05:41,000 --> 00:05:45,000
+You can find a link to the download page in attachments to this lesson.
+
+67
+00:05:45,000 --> 00:05:52,000
+You can find isn't active installer or zip archive was binaries for this tutorial and personally for
+
+68
+00:05:52,000 --> 00:05:55,000
+myself, I would download Interactive Installer.
+
+69
+00:05:56,000 --> 00:06:00,000
+I don't want to play hacker game and console to extract binaries.
+
+70
+00:06:00,000 --> 00:06:03,000
+Also, all examples from the slide off of Windows.
+
+71
+00:06:04,000 --> 00:06:07,000
+The similar stabs during the installation for Mac OS.
+
+72
+00:06:08,000 --> 00:06:10,000
+But just in case you can also.
+
+73
+00:06:10,000 --> 00:06:14,000
+Lines and attachments guide on how to install PostgreSQL on Mac.
+
+74
+00:06:15,000 --> 00:06:21,000
+Basically, after you selected your operating system, there is a separate page where you can select
+
+75
+00:06:21,000 --> 00:06:25,000
+what you would like to do, not binaries or installer.
+
+76
+00:06:25,000 --> 00:06:29,000
+You can make a cup of tea because downloading may take some time.
+
+77
+00:06:30,000 --> 00:06:31,000
+Once downloading is finished.
+
+78
+00:06:31,000 --> 00:06:35,000
+Runs interactive installer on the first step.
+
+79
+00:06:35,000 --> 00:06:36,000
+There is nothing special.
+
+80
+00:06:36,000 --> 00:06:37,000
+Just welcome message.
+
+81
+00:06:38,000 --> 00:06:39,000
+Click Next button.
+
+82
+00:06:40,000 --> 00:06:44,000
+On the next step, make sure you say it's a installation directory.
+
+83
+00:06:44,000 --> 00:06:47,000
+Once you are ready, click the next button.
+
+84
+00:06:48,000 --> 00:06:53,000
+On this step, we have to select PostgreSQL components that we want to install.
+
+85
+00:06:53,000 --> 00:06:56,000
+Let me explain you a little bit about each of this.
+
+86
+00:06:57,000 --> 00:07:01,000
+Well, PostgreSQL server, it is our core component.
+
+87
+00:07:01,000 --> 00:07:03,000
+You can treat it as databases.
+
+88
+00:07:03,000 --> 00:07:09,000
+So DG Admin is a client you are to interact with supposedly a SQL server.
+
+89
+00:07:10,000 --> 00:07:16,000
+The Stack Builder utility provides a graphical interface that simplifies the process of downloading
+
+90
+00:07:16,000 --> 00:07:21,000
+and installing modules that complement your Cosmos sequel installation.
+
+91
+00:07:22,000 --> 00:07:28,000
+When you install a module with Stack Builder, Stack Builder automatically resolves any software dependencies.
+
+92
+00:07:29,000 --> 00:07:36,000
+So this nice tool to have installed just in case and another component is a command line tools that
+
+93
+00:07:36,000 --> 00:07:40,000
+they use to interact with PostgreSQL with the help of command line.
+
+94
+00:07:41,000 --> 00:07:44,000
+I recommend you also to install this just in case.
+
+95
+00:07:45,000 --> 00:07:47,000
+After that, click next button.
+
+96
+00:07:47,000 --> 00:07:53,000
+After that, you have opportunity to configure passed as a folder where your data will be stored.
+
+97
+00:07:54,000 --> 00:08:00,000
+By default, you will be offered to create a data folder in PostgreSQL Installation Directory.
+
+98
+00:08:01,000 --> 00:08:04,000
+If this is OK for you, then just press next button.
+
+99
+00:08:05,000 --> 00:08:13,000
+On the next step, please write a password for a super user who has all rights in database having access
+
+100
+00:08:13,000 --> 00:08:19,000
+to this user, you can start creation of other users, schemas, tables and so on.
+
+101
+00:08:19,000 --> 00:08:21,000
+Please remember this password.
+
+102
+00:08:22,000 --> 00:08:23,000
+This is important.
+
+103
+00:08:24,000 --> 00:08:31,000
+Was Great Article is an app that will be running on our computer and to get connected to the PostgreSQL,
+
+104
+00:08:31,000 --> 00:08:34,000
+we need to know port number on this computer.
+
+105
+00:08:35,000 --> 00:08:40,000
+And the biggest lesson when we installed my I explained what is port number.
+
+106
+00:08:41,000 --> 00:08:46,000
+Also, I have separate course about that programming where I cover network concept.
+
+107
+00:08:46,000 --> 00:08:48,000
+Just to remind you a few words about Port.
+
+108
+00:08:48,000 --> 00:08:49,000
+No.
+
+109
+00:08:49,000 --> 00:08:52,000
+We are going to use it as part of address.
+
+110
+00:08:52,000 --> 00:09:00,000
+One will connect to the possible SQL server, and if IP address is an address of our machines network,
+
+111
+00:09:01,000 --> 00:09:05,000
+then port number is an address of the app on this specific machine.
+
+112
+00:09:06,000 --> 00:09:14,000
+The default port, of course, with a sequel, is 54 so that you can change it if you wish.
+
+113
+00:09:14,000 --> 00:09:20,000
+And if for some reason this sport is already captured by other app, in my case, I just click next
+
+114
+00:09:21,000 --> 00:09:24,000
+select lock collar that works the best for you.
+
+115
+00:09:25,000 --> 00:09:29,000
+This configuration will impact all the collaboration settings of the app.
+
+116
+00:09:29,000 --> 00:09:32,000
+Don't worry, you will be able to change this later, too.
+
+117
+00:09:33,000 --> 00:09:40,000
+You can keep the folder color option and click Next button on this snap check installation information.
+
+118
+00:09:40,000 --> 00:09:46,000
+And if everything looks good to you, press it to the next step and start installation.
+
+119
+00:09:47,000 --> 00:09:52,000
+If installation finished successfully, you would see a notification about installation completion.
+
+120
+00:09:53,000 --> 00:09:55,000
+You will be offered the launch stack builder.
+
+121
+00:09:56,000 --> 00:09:58,000
+You can keep this checkbox marked if you wish.
+
+122
+00:09:59,000 --> 00:10:02,000
+And afterwards, just press finish button.
+
+123
+00:10:02,000 --> 00:10:03,000
+And that's it.
+
+124
+00:10:03,000 --> 00:10:09,000
+Congrats, PostgreSQL installed on your computer with all other components.
+
+125
+00:10:09,000 --> 00:10:15,000
+So in case you kept chequebooks smart, you would have struggled to open.
+
+126
+00:10:15,000 --> 00:10:18,000
+But what to do with it in the future?
+
+127
+00:10:18,000 --> 00:10:25,000
+You can run it separately in case you want to install some advanced PostgreSQL, for example.
+
+128
+00:10:25,000 --> 00:10:29,000
+On the slide, you can see just an example of what can be installed.
+
+129
+00:10:30,000 --> 00:10:33,000
+We don't need anything from this list at this moment.
+
+130
+00:10:33,000 --> 00:10:35,000
+Sewa Just Glow Stack Builder.
+
+131
+00:10:36,000 --> 00:10:43,000
+Let's understand now how to run PostgreSQL, and let's test that interaction with databases is configured
+
+132
+00:10:43,000 --> 00:10:43,000
+properly.
+
+133
+00:10:44,000 --> 00:10:50,000
+And various lessons, I also explained you what Windows service is just to remind you.
+
+134
+00:10:50,000 --> 00:10:58,000
+Windows services are core components of the Microsoft Windows operating system and enables the creation
+
+135
+00:10:58,000 --> 00:11:02,000
+and management of long running processes right after installation.
+
+136
+00:11:03,000 --> 00:11:06,000
+You have PostgreSQL Windows service up and running.
+
+137
+00:11:06,000 --> 00:11:10,000
+You can check this by opening services on your Windows machine.
+
+138
+00:11:10,000 --> 00:11:16,000
+Also in this place, you can either stop the service or configure startup time.
+
+139
+00:11:16,000 --> 00:11:23,000
+For example, I keep my school service started automatically, started that and my PostgreSQL service
+
+140
+00:11:23,000 --> 00:11:29,000
+I keep in manual starts up because I don't see a lot of reasons to load.
+
+141
+00:11:29,000 --> 00:11:32,000
+My machine was to databases run in Perl.
+
+142
+00:11:32,000 --> 00:11:36,000
+Definitely for this demo I turned PostgreSQL service on.
+
+143
+00:11:37,000 --> 00:11:40,000
+Now you know the place where this may be configured.
+
+144
+00:11:41,000 --> 00:11:41,000
+Great.
+
+145
+00:11:42,000 --> 00:11:46,000
+Now, let's learn how to work with supposedly equals through the nice UI.
+
+146
+00:11:46,000 --> 00:11:53,000
+We have separate applications that we have also already installed and that the so-called admin to start
+
+147
+00:11:53,000 --> 00:11:57,000
+at least navigate to the installation directory of possible sequel.
+
+148
+00:11:58,000 --> 00:12:01,000
+You're going to find a separate folder was named A.G. Admin.
+
+149
+00:12:02,000 --> 00:12:06,000
+Open it and find the executable file with the same name.
+
+150
+00:12:07,000 --> 00:12:11,000
+Double click it and Beijing admin app will start loading.
+
+151
+00:12:12,000 --> 00:12:16,000
+On the first start up, you will be asked to set and must have passwords for page admin.
+
+152
+00:12:17,000 --> 00:12:23,000
+This is needed because potentially you can have multiple connections and server configuration stored
+
+153
+00:12:23,000 --> 00:12:26,000
+in the app to secure the setup on each startup.
+
+154
+00:12:26,000 --> 00:12:34,000
+This app will ask you a master password, so also remember the password and press OK button?
+
+155
+00:12:35,000 --> 00:12:38,000
+The next thing that we need to do is to connect through an existing server.
+
+156
+00:12:38,000 --> 00:12:40,000
+We have page admin.
+
+157
+00:12:40,000 --> 00:12:47,000
+You just need to expand servers in the left panel and you will find the server that's already exists
+
+158
+00:12:47,000 --> 00:12:48,000
+on your local hosts.
+
+159
+00:12:49,000 --> 00:12:52,000
+This is exactly the server that we have just installed.
+
+160
+00:12:52,000 --> 00:12:59,000
+Click on it and you will be prompted to enter your password and to share passwords with you, said during
+
+161
+00:12:59,000 --> 00:13:00,000
+the installation.
+
+162
+00:13:01,000 --> 00:13:04,000
+You can save passwords in page admin if you wish.
+
+163
+00:13:04,000 --> 00:13:06,000
+And press OK button.
+
+164
+00:13:07,000 --> 00:13:08,000
+Congrats, team.
+
+165
+00:13:08,000 --> 00:13:10,000
+We managed to connect to our Sara.
+
+166
+00:13:11,000 --> 00:13:17,000
+That is great on the home page, you can see some charts and information about performance.
+
+167
+00:13:17,000 --> 00:13:21,000
+There are also a lot of other things that we can do from this point.
+
+168
+00:13:21,000 --> 00:13:25,000
+But all of this will be discussed in separate lessons in details.
+
+169
+00:13:26,000 --> 00:13:31,000
+The most important thing is that you successfully managed to connect as a possible SQL server.
+
+170
+00:13:32,000 --> 00:13:34,000
+Let me show you one more interesting thing.
+
+171
+00:13:34,000 --> 00:13:40,000
+You can always connect the remote database knowing the exact address of the PostgreSQL.
+
+172
+00:13:41,000 --> 00:13:48,000
+Let me show you now how to add new silver collection service and then click Add New Server.
+
+173
+00:13:49,000 --> 00:13:56,000
+Now we need just some information about servers that we want to connect on the general tap.
+
+174
+00:13:56,000 --> 00:14:01,000
+Just enter the names that would be easy to recognize for you and Server Group.
+
+175
+00:14:01,000 --> 00:14:07,000
+You can group different service together to navigate easily between them later when needed.
+
+176
+00:14:08,000 --> 00:14:14,000
+After that, you need to choose connection type to the server and configure it separately in the top
+
+177
+00:14:14,000 --> 00:14:14,000
+bar.
+
+178
+00:14:14,000 --> 00:14:16,000
+You can see different apps.
+
+179
+00:14:16,000 --> 00:14:18,000
+They are connection.
+
+180
+00:14:18,000 --> 00:14:20,000
+This one is for connections.
+
+181
+00:14:20,000 --> 00:14:23,000
+We are TCP IP Protocol SSL.
+
+182
+00:14:24,000 --> 00:14:27,000
+This step is to configure connection with SSL.
+
+183
+00:14:28,000 --> 00:14:30,000
+SSL stands for Secure Sockets Layer.
+
+184
+00:14:31,000 --> 00:14:34,000
+And again, we're going to learn web in a separate course.
+
+185
+00:14:35,000 --> 00:14:40,000
+This protocol runs on top of this IP protocol as a secret tunnel.
+
+186
+00:14:41,000 --> 00:14:44,000
+On that one tab, you can configure SSL connection.
+
+187
+00:14:45,000 --> 00:14:52,000
+In no particular case, I want to use Connection tab to configure connection with TCP IP protocol in
+
+188
+00:14:52,000 --> 00:14:53,000
+host address.
+
+189
+00:14:53,000 --> 00:14:55,000
+You should put the address of the host.
+
+190
+00:14:55,000 --> 00:14:57,000
+Usually, this is an IP address.
+
+191
+00:14:58,000 --> 00:15:01,000
+In this example, I'm going to connect to my localhost.
+
+192
+00:15:02,000 --> 00:15:07,000
+This IP always refers to the local host, or you can just use local hostname.
+
+193
+00:15:07,000 --> 00:15:14,000
+In this particular example, localhost is a hostname which refers to the current computer used to access
+
+194
+00:15:14,000 --> 00:15:14,000
+it.
+
+195
+00:15:15,000 --> 00:15:23,000
+I use default port for possible sequel, so I put value 50 four course suited to in the ports field
+
+196
+00:15:23,000 --> 00:15:25,000
+in maintenance database.
+
+197
+00:15:25,000 --> 00:15:28,000
+Put Pause Grass What is maintenance database?
+
+198
+00:15:28,000 --> 00:15:34,000
+Zip Postgres database is also created when a database cluster is initialized.
+
+199
+00:15:35,000 --> 00:15:41,000
+This database is meant as a default database for users and applications to connect to.
+
+200
+00:15:41,000 --> 00:15:45,000
+After that, we need to specify a name of the user.
+
+201
+00:15:45,000 --> 00:15:49,000
+The name of our admin user by default is progress.
+
+202
+00:15:50,000 --> 00:15:53,000
+Also, we have to use the password for this user.
+
+203
+00:15:53,000 --> 00:15:58,000
+And after all configurations are on, please just click Save button.
+
+204
+00:15:59,000 --> 00:16:02,000
+That's all what I wanted to share with you in this lesson.
+
+205
+00:16:02,000 --> 00:16:08,000
+Let's recap what we have learned today in this lesson we hold PostgreSQL over.
+
+206
+00:16:08,000 --> 00:16:10,000
+You removed its main features.
+
+207
+00:16:11,000 --> 00:16:15,000
+After that, we proceed with the practice space to prepare environment.
+
+208
+00:16:15,000 --> 00:16:21,000
+We installed Postgres, SQL Server, PJ Admin, Stack Builder and command line tools.
+
+209
+00:16:22,000 --> 00:16:25,000
+I showed you an example How to connect to Postgres SQL Server.
+
+210
+00:16:25,000 --> 00:16:30,000
+We are Pidgey admin and how to create a new server inside paging admin.
+
+211
+00:16:31,000 --> 00:16:37,000
+Also, I explained how and where you can configure Windows servers for Postgres sequel.
+
+212
+00:16:38,000 --> 00:16:40,000
+Thank you all team for your attention.
+
+213
+00:16:40,000 --> 00:16:43,000
+Have a great day and see you in the next lesson.
+

46 - Databases Overview and Environment Setup/005 PostgreSQL-download.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://www.postgresql.org/download/

46 - Databases Overview and Environment Setup/external-links.txt

@@ -0,0 +1,12 @@
+
+004 Microsoft-MySQL-Installer
+https://dev.mysql.com/downloads/installer/
+
+004 How-to-Install-MySQL-on-MacOS
+https://dev.mysql.com/doc/refman/8.0/en/macos-installation-pkg.html
+
+005 PostgreSQL-download
+https://www.postgresql.org/download/
+
+005 Guide-How-to-install-PostgreSQL-on-Mac
+https://www.postgresqltutorial.com/install-postgresql-macos/

47 - Relational databases/001 Relational Databases Basic Concepts_en.srt

@@ -0,0 +1,1320 @@
+1
+00:00:05,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:10,000
+And this last one, we're going to start learning the relational databases.
+
+3
+00:00:11,000 --> 00:00:17,000
+We're going to start from understanding of basic concepts and gradually we'll move to more complicated
+
+4
+00:00:17,000 --> 00:00:17,000
+topics.
+
+5
+00:00:18,000 --> 00:00:26,000
+We're going to start our lesson with learning such basic terms a stable entity, absolute chapel records,
+
+6
+00:00:26,000 --> 00:00:32,000
+etc. separate focus on the good and the differences between database and schema.
+
+7
+00:00:32,000 --> 00:00:38,000
+Because very often my students ask me what is schema and how it is different from database.
+
+8
+00:00:39,000 --> 00:00:43,000
+After that, we are going to learn such important concept as primary key.
+
+9
+00:00:43,000 --> 00:00:48,000
+I will share with you different examples, and that will help you to understand the difference between
+
+10
+00:00:48,000 --> 00:00:52,000
+simple and compound key, natural and surrogate key.
+
+11
+00:00:53,000 --> 00:00:58,000
+Also, you will learn what alternate care is to understand relationships in databases.
+
+12
+00:00:58,000 --> 00:01:05,000
+We need to learn what foreign key is, and once we learn all these terms will start none of the relationships
+
+13
+00:01:05,000 --> 00:01:06,000
+in relational databases.
+
+14
+00:01:07,000 --> 00:01:12,000
+You're going to understand what types of relationship we have and how they're different from each other.
+
+15
+00:01:13,000 --> 00:01:19,000
+Let's start our lesson before we start dive deeper into the details of relational databases.
+
+16
+00:01:20,000 --> 00:01:25,000
+Let's learn some basic terms that we are going to use during today's lesson and future lessons.
+
+17
+00:01:25,000 --> 00:01:29,000
+Let's go over each channel one by one database.
+
+18
+00:01:30,000 --> 00:01:35,000
+We use this term usually to refer to a set of tables with some data in them.
+
+19
+00:01:36,000 --> 00:01:36,000
+Is that clear?
+
+20
+00:01:37,000 --> 00:01:38,000
+I believe there is one more question.
+
+21
+00:01:39,000 --> 00:01:40,000
+What are tables?
+
+22
+00:01:41,000 --> 00:01:47,000
+Tables and metrics with data of the specified format in table, you have rows and columns.
+
+23
+00:01:47,000 --> 00:01:49,000
+Each column has name.
+
+24
+00:01:49,000 --> 00:01:56,000
+Also, each column has data that we can specify what kind of data will be stored in this column.
+
+25
+00:01:57,000 --> 00:02:03,000
+Topple in relational databases, we use this term to describe one records of data.
+
+26
+00:02:03,000 --> 00:02:06,000
+OK, so what is the records?
+
+27
+00:02:06,000 --> 00:02:09,000
+Records is one row in table.
+
+28
+00:02:09,000 --> 00:02:16,000
+Let's continue with other terms is we need to be familiar with entity and entity is distinguishable.
+
+29
+00:02:16,000 --> 00:02:23,000
+The real world object that exists and the object should not be considered as an entity until it can
+
+30
+00:02:23,000 --> 00:02:27,000
+be easily identified from all other objects of the real world.
+
+31
+00:02:28,000 --> 00:02:36,000
+In other simple words, if you can't identify sets of characteristics that define some object in a unique
+
+32
+00:02:36,000 --> 00:02:43,000
+way, which allows you to store data about objects or if you are not going to retrieve data about some
+
+33
+00:02:43,000 --> 00:02:48,000
+object, then there is no point in creating that entity in a database.
+
+34
+00:02:49,000 --> 00:02:50,000
+Does it make sense?
+
+35
+00:02:51,000 --> 00:02:58,000
+Attribute Attribute is a characteristic in a database management system and attributes refers to database
+
+36
+00:02:58,000 --> 00:03:05,000
+field attributes, describes the characteristics or properties of an entity in a database table and
+
+37
+00:03:05,000 --> 00:03:10,000
+the entity in a database table is defined was a fixed set of actions.
+
+38
+00:03:11,000 --> 00:03:16,000
+For example, you will have to define a user entity that we can define.
+
+39
+00:03:16,000 --> 00:03:20,000
+It was a set of attributes like email, name, etc..
+
+40
+00:03:21,000 --> 00:03:27,000
+The attribute values of each user entity will define its characteristics in the table.
+
+41
+00:03:28,000 --> 00:03:36,000
+In most simple words, attributes are columns in database tables, and each row has set of common values.
+
+42
+00:03:36,000 --> 00:03:40,000
+Those are attributes, but this is very simplified definition.
+
+43
+00:03:41,000 --> 00:03:48,000
+There is also one more chance that we have learned to use often today in the lesson schema analysis
+
+44
+00:03:48,000 --> 00:03:53,000
+schema is an abstract designs its represent the storage of your data in a database.
+
+45
+00:03:53,000 --> 00:04:01,000
+It describes both zircon zation of data and the relationships between tables in a given database.
+
+46
+00:04:01,000 --> 00:04:07,000
+Sometimes you can find that people use schema and database as interchangeable terms.
+
+47
+00:04:07,000 --> 00:04:09,000
+But this is not correct.
+
+48
+00:04:09,000 --> 00:04:16,000
+The fundamental difference between them is that the database is an organized collection of internal
+
+49
+00:04:16,000 --> 00:04:23,000
+data data, and on the other hand, the schema is a logical representation or description of an entire
+
+50
+00:04:23,000 --> 00:04:23,000
+database.
+
+51
+00:04:24,000 --> 00:04:31,000
+Schema contains the structure of tables, attributes that types, constraints and how they relate to
+
+52
+00:04:31,000 --> 00:04:32,000
+other tables.
+
+53
+00:04:32,000 --> 00:04:35,000
+Do you feel the difference between these two terms?
+
+54
+00:04:36,000 --> 00:04:38,000
+These are just basic terms.
+
+55
+00:04:38,000 --> 00:04:39,000
+Tsarist jumps were.
+
+56
+00:04:39,000 --> 00:04:42,000
+I go on to those examples as we go.
+
+57
+00:04:42,000 --> 00:04:43,000
+Is that clear?
+
+58
+00:04:44,000 --> 00:04:46,000
+If yes, then let's proceed.
+
+59
+00:04:47,000 --> 00:04:50,000
+Another important term in a relational databases is a primary key.
+
+60
+00:04:51,000 --> 00:04:58,000
+I decided to dedicate a separate slide to reviews the definition so primary key is a specific choice
+
+61
+00:04:58,000 --> 00:05:00,000
+of minimal set of attributes.
+
+62
+00:05:00,000 --> 00:05:07,000
+And you already know that attributes many columns that uniquely identify, topple and you learn, you
+
+63
+00:05:07,000 --> 00:05:11,000
+know, that tadpole is a synonym to row in the table.
+
+64
+00:05:11,000 --> 00:05:19,000
+In most simple words, primary key is an attribute or unique set of attributes that can identify specific
+
+65
+00:05:19,000 --> 00:05:21,000
+rule in the book, among others.
+
+66
+00:05:22,000 --> 00:05:28,000
+And if you would ask me to come up with even simple definition, I would say is its primary key is a
+
+67
+00:05:28,000 --> 00:05:29,000
+unique idea.
+
+68
+00:05:30,000 --> 00:05:35,000
+We are going to build a relationship between tables and being more specific.
+
+69
+00:05:35,000 --> 00:05:41,000
+We would build relationships with the two in one table with data in another table.
+
+70
+00:05:41,000 --> 00:05:49,000
+That means we need to find a way to uniquely identify each role in each table to connect them between
+
+71
+00:05:49,000 --> 00:05:49,000
+each other.
+
+72
+00:05:50,000 --> 00:05:53,000
+That's why primary key is so important.
+
+73
+00:05:53,000 --> 00:05:56,000
+Let's come up with the ideas of primary key.
+
+74
+00:05:57,000 --> 00:06:03,000
+The first goal is to uniquely identify to people in the database table, and the second goal is to ensure
+
+75
+00:06:03,000 --> 00:06:04,000
+connection between tables.
+
+76
+00:06:05,000 --> 00:06:06,000
+Is that clear?
+
+77
+00:06:06,000 --> 00:06:13,000
+And always remember that in case of any questions exam, you can put your question below this reader
+
+78
+00:06:13,000 --> 00:06:15,000
+and I will be happy to answer it.
+
+79
+00:06:16,000 --> 00:06:23,000
+But how to choose the primary key, among other attributes, what rules should be applied or what is
+
+80
+00:06:23,000 --> 00:06:30,000
+the best practices zero of some is to select the shortest possible field if you understand what I mean.
+
+81
+00:06:30,000 --> 00:06:33,000
+What's the shortest possible combination of fields?
+
+82
+00:06:33,000 --> 00:06:36,000
+By saying this, I pursue one goal.
+
+83
+00:06:36,000 --> 00:06:39,000
+Primary key should be simple enough to work.
+
+84
+00:06:39,000 --> 00:06:44,000
+It should be atomic and shouldn't consist from multiple values inside one field.
+
+85
+00:06:45,000 --> 00:06:50,000
+It should be unique, and achieving this uniqueness shouldn't be hard thing to do.
+
+86
+00:06:51,000 --> 00:06:58,000
+I mean is easy to find, not unique first name, and it is impossible to find the same email.
+
+87
+00:06:58,000 --> 00:07:05,000
+That means that achieving uniqueness for email field is more simple, and it is better option to use
+
+88
+00:07:05,000 --> 00:07:06,000
+for primary key.
+
+89
+00:07:06,000 --> 00:07:10,000
+And obviously, primary key can't be no value.
+
+90
+00:07:11,000 --> 00:07:12,000
+To send my point.
+
+91
+00:07:13,000 --> 00:07:21,000
+Another important classification is its primary key may be simple and compound interest and in simple
+
+92
+00:07:21,000 --> 00:07:25,000
+words, simple primary key consists of the one people felt.
+
+93
+00:07:25,000 --> 00:07:34,000
+This can be an email I the best for no or anything else what is unique for each row in table and fits
+
+94
+00:07:34,000 --> 00:07:35,000
+in one field?
+
+95
+00:07:36,000 --> 00:07:44,000
+On the other hand, Compound's primary key consists of two or more fields, so the combination of these
+
+96
+00:07:44,000 --> 00:07:46,000
+fields should be unique.
+
+97
+00:07:47,000 --> 00:07:54,000
+For example, I have online courses and each course has I.D. That is, of course, primary key.
+
+98
+00:07:54,000 --> 00:08:01,000
+Also, I have students and each student has its own unique identifier, and let's imagine that I need
+
+99
+00:08:01,000 --> 00:08:04,000
+to store information about enrollments.
+
+100
+00:08:04,000 --> 00:08:12,000
+In my course, I have an enrollment table that has Compound's primary key that consists of two values,
+
+101
+00:08:12,000 --> 00:08:21,000
+namely courses plus student I.D. And there is information that people like the date of enrollment,
+
+102
+00:08:21,000 --> 00:08:29,000
+growth, speed, discount applied or any other possible field can be easily connected and identified
+
+103
+00:08:29,000 --> 00:08:31,000
+with this compound primary key.
+
+104
+00:08:31,000 --> 00:08:32,000
+Does it make sense?
+
+105
+00:08:33,000 --> 00:08:39,000
+To be honest, Compound's primary keys are less often than simple primary kiss.
+
+106
+00:08:39,000 --> 00:08:47,000
+But still they exist, and I'm going to teach you how to create compounds primary keys in the database.
+
+107
+00:08:47,000 --> 00:08:50,000
+In a separate lesson, you're in the practice exercise.
+
+108
+00:08:51,000 --> 00:08:55,000
+And that's the classification of primary key depends on its origins.
+
+109
+00:08:56,000 --> 00:09:04,000
+Primary key may be natural a surrogate surrogate primary keys also called synthetic, sometimes in simple
+
+110
+00:09:04,000 --> 00:09:05,000
+words, is a natural primary.
+
+111
+00:09:05,000 --> 00:09:09,000
+Key is a field that stores useful information.
+
+112
+00:09:09,000 --> 00:09:14,000
+For example, desperate number may be unique for a person, but this is also values.
+
+113
+00:09:14,000 --> 00:09:18,000
+It contains information related to specific person.
+
+114
+00:09:18,000 --> 00:09:19,000
+This is real.
+
+115
+00:09:19,000 --> 00:09:24,000
+Data is accurate naturally, and just records the same situation with email.
+
+116
+00:09:25,000 --> 00:09:28,000
+Email may be considered as national primary key.
+
+117
+00:09:29,000 --> 00:09:32,000
+National keys have one logical advantage, in my opinion.
+
+118
+00:09:32,000 --> 00:09:35,000
+It sounds like this is it the search.
+
+119
+00:09:36,000 --> 00:09:42,000
+Since Natural Ki contains some valuable information, it is easier for you to understand this information.
+
+120
+00:09:42,000 --> 00:09:49,000
+For example, it will be hard to remember sequence number for each user to search user, but it's the
+
+121
+00:09:49,000 --> 00:09:56,000
+but instead it will be easier to memorize user email and search user by its email.
+
+122
+00:09:56,000 --> 00:10:04,000
+Natural primary keys have some disadvantages, though the most important are take more memory to store
+
+123
+00:10:04,000 --> 00:10:06,000
+rather than surrogate key.
+
+124
+00:10:07,000 --> 00:10:14,000
+This means that you will require more memory to store the data, and also this means is a joint request
+
+125
+00:10:14,000 --> 00:10:22,000
+on multiple tables might take more time because usually natural keys are strings but not integers,
+
+126
+00:10:22,000 --> 00:10:25,000
+and it takes time to compare strings.
+
+127
+00:10:26,000 --> 00:10:29,000
+Requires cascading update in case of changing.
+
+128
+00:10:29,000 --> 00:10:38,000
+Imagine that you use email as a primary key and user decided to change email, we forbid him to do so.
+
+129
+00:10:39,000 --> 00:10:40,000
+Of course not.
+
+130
+00:10:40,000 --> 00:10:42,000
+He changes email.
+
+131
+00:10:42,000 --> 00:10:49,000
+After that, we have to update email everywhere where we used his primary key to build relationships
+
+132
+00:10:50,000 --> 00:10:52,000
+basically in other tables.
+
+133
+00:10:52,000 --> 00:10:59,000
+Definitely, this operation will take some time dependent on a number of changes that we have to make.
+
+134
+00:11:00,000 --> 00:11:03,000
+But why should we do these cascading changes?
+
+135
+00:11:03,000 --> 00:11:10,000
+If we could avoid doing them at all and one more problems that you might face with while using natural
+
+136
+00:11:10,000 --> 00:11:16,000
+key, there might be cases when you just don't have all the necessary information all the time.
+
+137
+00:11:16,000 --> 00:11:21,000
+Imagine that in the application, you also supports registration with a phone number.
+
+138
+00:11:22,000 --> 00:11:29,000
+User can choose whether he or she wants to use phone number or email for authorization.
+
+139
+00:11:29,000 --> 00:11:31,000
+And what should we do in this case?
+
+140
+00:11:32,000 --> 00:11:33,000
+It is hard to answer.
+
+141
+00:11:33,000 --> 00:11:40,000
+You would have to come up with some email that you don't have in order to fill out the primary key.
+
+142
+00:11:40,000 --> 00:11:46,000
+And what will happen when you start sending you say that you are going to send an email to the false
+
+143
+00:11:46,000 --> 00:11:47,000
+address?
+
+144
+00:11:47,000 --> 00:11:54,000
+Well, the see what problems may appear to address all issues mentioned above.
+
+145
+00:11:54,000 --> 00:11:56,000
+You can just use surrogate key.
+
+146
+00:11:57,000 --> 00:12:04,000
+On the contrary to natural case surrogates, kid doesn't have a natural relationship with the rest data
+
+147
+00:12:04,000 --> 00:12:05,000
+in the record.
+
+148
+00:12:05,000 --> 00:12:13,000
+That's why, no matter how records will change, your surrogate key will stay the same because its only
+
+149
+00:12:13,000 --> 00:12:17,000
+goal is to identify records in the table.
+
+150
+00:12:17,000 --> 00:12:19,000
+That's it, and nothing more.
+
+151
+00:12:20,000 --> 00:12:27,000
+Usually, this is integer value that is incremented with each new row, and you are not Borsa at Wiscasset
+
+152
+00:12:27,000 --> 00:12:31,000
+in need or thinking about any false value.
+
+153
+00:12:31,000 --> 00:12:36,000
+I recommend it to use surrogate keys, but this will be only up to you.
+
+154
+00:12:36,000 --> 00:12:41,000
+Summarizing limbo, let's come up with advantages of surrogates.
+
+155
+00:12:41,000 --> 00:12:47,000
+Case surrogate Qi has no any business related information built in it.
+
+156
+00:12:47,000 --> 00:12:50,000
+This makes sinks easier.
+
+157
+00:12:50,000 --> 00:12:54,000
+We shouldn't worry about updating it in all related tables.
+
+158
+00:12:55,000 --> 00:13:01,000
+Performing cascading operations in case some business related information from primary key has been
+
+159
+00:13:01,000 --> 00:13:02,000
+changed.
+
+160
+00:13:02,000 --> 00:13:10,000
+Also, this type of case takes less memory because usually we use integer time for surrogate keys,
+
+161
+00:13:10,000 --> 00:13:12,000
+and this is only four bytes.
+
+162
+00:13:12,000 --> 00:13:17,000
+Usually, requests on different tables also completed faster.
+
+163
+00:13:17,000 --> 00:13:23,000
+Usually, there are no reasons to change surrogate qi because it is just and then the fire.
+
+164
+00:13:24,000 --> 00:13:29,000
+Thus, there is no need in cascading need of the value in all related tables.
+
+165
+00:13:30,000 --> 00:13:37,000
+And the only drawback is that I see in using surrogate integer key is that it can limit the number of
+
+166
+00:13:37,000 --> 00:13:43,000
+rows in the table because at the end of the day, we have limited amount of memory reserved for data
+
+167
+00:13:43,000 --> 00:13:47,000
+of integer type that is four bytes only.
+
+168
+00:13:47,000 --> 00:13:52,000
+But on the other hand, you can use unsigned integer value.
+
+169
+00:13:53,000 --> 00:13:59,000
+This gives you opportunity to use one low need to store additional information, and in total, you
+
+170
+00:13:59,000 --> 00:14:02,000
+can create more than four billion the rules.
+
+171
+00:14:03,000 --> 00:14:08,000
+And believe me, if you have more than four million records in your table, you're going to have a lot
+
+172
+00:14:08,000 --> 00:14:11,000
+of other problems besides limit of integer value.
+
+173
+00:14:12,000 --> 00:14:18,000
+And if you have four billion users registered in your app, you have enough resources to apply workarounds
+
+174
+00:14:18,000 --> 00:14:18,000
+for this issue.
+
+175
+00:14:19,000 --> 00:14:24,000
+One was a solution, maybe is to create table was big and start for primary care.
+
+176
+00:14:25,000 --> 00:14:30,000
+This data type use eight bytes to store information, which should be enough.
+
+177
+00:14:31,000 --> 00:14:37,000
+And after that, you can copy and paste rows from one table to another and update the last tidy value
+
+178
+00:14:37,000 --> 00:14:42,000
+for all the increment in order you can proceed, adding new ideas for new records.
+
+179
+00:14:43,000 --> 00:14:48,000
+Don't worry, I'm going to show you how to do this on practice in the following lessons.
+
+180
+00:14:49,000 --> 00:14:54,000
+We already know what's primary case and learned different classifications of primary case.
+
+181
+00:14:55,000 --> 00:15:04,000
+Now let me explain what alternate care is there also called sometimes secondary case alternate case
+
+182
+00:15:04,000 --> 00:15:11,000
+as those candidates case, which are not the primary care since there's only one primary care for a
+
+183
+00:15:11,000 --> 00:15:11,000
+table.
+
+184
+00:15:11,000 --> 00:15:19,000
+Other fields that are also unique and can be used for Typekit identification are called alternate case.
+
+185
+00:15:19,000 --> 00:15:25,000
+For example, imagine that you have table was users and you decided to use surrogate primary care,
+
+186
+00:15:25,000 --> 00:15:29,000
+but you also have another column that contains only unique values.
+
+187
+00:15:30,000 --> 00:15:33,000
+It can be common with emails, for example.
+
+188
+00:15:33,000 --> 00:15:38,000
+Indeed, it is impossible that users will have the same email the system.
+
+189
+00:15:39,000 --> 00:15:43,000
+But database administrator decided to use it as a primary key.
+
+190
+00:15:44,000 --> 00:15:51,000
+We unique restriction to a mail column and still can use it to extract user when needed.
+
+191
+00:15:51,000 --> 00:15:55,000
+But this attribute may be considered as an alternate care.
+
+192
+00:15:55,000 --> 00:15:56,000
+Is that clear?
+
+193
+00:15:57,000 --> 00:15:59,000
+Now let's look at another important term.
+
+194
+00:15:59,000 --> 00:16:02,000
+Let me explain what foreign key is.
+
+195
+00:16:02,000 --> 00:16:09,000
+One key is an attribute which is primary key in its parent table, but is included as an action.
+
+196
+00:16:09,000 --> 00:16:16,000
+But in another table with the goal to establish connection between entities, we already know that in
+
+197
+00:16:16,000 --> 00:16:24,000
+relational database we may have different tables and tables will be connected with each other to avoid
+
+198
+00:16:24,000 --> 00:16:30,000
+data duplication and to ensure the most efficient and consistent data storage neutrally.
+
+199
+00:16:30,000 --> 00:16:36,000
+In the minute, you're going to see examples how relationships between different tables are established.
+
+200
+00:16:37,000 --> 00:16:40,000
+So now you know what primary key and foreign key is.
+
+201
+00:16:41,000 --> 00:16:47,000
+That means we can learn type of relationships and understand technical side of establishing connections
+
+202
+00:16:47,000 --> 00:16:48,000
+between tables.
+
+203
+00:16:49,000 --> 00:16:52,000
+First of all, let's understand what relationship is.
+
+204
+00:16:53,000 --> 00:17:00,000
+There is a definition from a relational database theory that was defined by Edgar Frankel, inventor
+
+205
+00:17:00,000 --> 00:17:03,000
+of relational model database management.
+
+206
+00:17:03,000 --> 00:17:09,000
+But instead of reading that definition, I'm going to explain you what relationship is, in simple words,
+
+207
+00:17:10,000 --> 00:17:16,000
+relationship in a relational database management system using an association of records from two or
+
+208
+00:17:16,000 --> 00:17:17,000
+more tables.
+
+209
+00:17:18,000 --> 00:17:23,000
+Let me also explain the relationship on example from real life user has a car.
+
+210
+00:17:24,000 --> 00:17:30,000
+This is a relationship between the user of the car and dependent on the number of objects from each
+
+211
+00:17:30,000 --> 00:17:31,000
+side of this relationship.
+
+212
+00:17:32,000 --> 00:17:35,000
+Then different types of relationship is that clear.
+
+213
+00:17:36,000 --> 00:17:39,000
+In the relational database, there are three types of relationships.
+
+214
+00:17:40,000 --> 00:17:42,000
+They are one to many.
+
+215
+00:17:43,000 --> 00:17:48,000
+That is when one user math many cars matter to many.
+
+216
+00:17:48,000 --> 00:17:57,000
+One user may have a lot of cars and one car may be owned by two users, by two co-owners and one to
+
+217
+00:17:57,000 --> 00:17:58,000
+one.
+
+218
+00:17:58,000 --> 00:18:03,000
+This relationship one one user can own one car only.
+
+219
+00:18:04,000 --> 00:18:10,000
+And now I'd like you to understand each of these relationship types, one by one in details, we'll
+
+220
+00:18:10,000 --> 00:18:13,000
+try to understand that logical first.
+
+221
+00:18:13,000 --> 00:18:20,000
+And after that, I will provide technical explanation on how this is implemented on database level one
+
+222
+00:18:20,000 --> 00:18:27,000
+to many means that one object from one table may be related to many objects from another table.
+
+223
+00:18:28,000 --> 00:18:31,000
+Now, a particular example was user and car.
+
+224
+00:18:31,000 --> 00:18:34,000
+We can apply want the money relationship in the next week?
+
+225
+00:18:34,000 --> 00:18:40,000
+One user may own multiple cars, but each car has only one user.
+
+226
+00:18:41,000 --> 00:18:43,000
+This is equal to one to many relationship.
+
+227
+00:18:44,000 --> 00:18:46,000
+One user owning many cars.
+
+228
+00:18:46,000 --> 00:18:47,000
+Does it make sense?
+
+229
+00:18:48,000 --> 00:18:53,000
+If you understood it logically, let's learn how this is implemented on database level.
+
+230
+00:18:54,000 --> 00:19:01,000
+Each relationship is implemented by migration of primary care from parent table in the direction of
+
+231
+00:19:01,000 --> 00:19:01,000
+another table.
+
+232
+00:19:02,000 --> 00:19:07,000
+The fields that we received after this migration is called foreign key.
+
+233
+00:19:08,000 --> 00:19:11,000
+In this example, we have table user and table car.
+
+234
+00:19:12,000 --> 00:19:16,000
+We add new column and table car that is called user I.D..
+
+235
+00:19:17,000 --> 00:19:23,000
+This will be a column as a source for Enki and for each car of specific user.
+
+236
+00:19:24,000 --> 00:19:29,000
+We pulled his I.D. and that's it was successfully established relationship.
+
+237
+00:19:30,000 --> 00:19:33,000
+Now you can query these two tables together.
+
+238
+00:19:33,000 --> 00:19:42,000
+For example, your query may sound like this return we can manufacture of each car that belongs to the
+
+239
+00:19:42,000 --> 00:19:50,000
+user was a new one and user email, and you have enough information to map records from two tables between
+
+240
+00:19:50,000 --> 00:19:51,000
+each other.
+
+241
+00:19:52,000 --> 00:19:53,000
+Do you understand?
+
+242
+00:19:54,000 --> 00:20:00,000
+In our sequel lesson, I will teach you how to grade school queries to retrieve this kind of information.
+
+243
+00:20:01,000 --> 00:20:03,000
+But is it clear for you, at least on the high level?
+
+244
+00:20:04,000 --> 00:20:11,000
+Remember, understanding the concept is much more important rather than understanding of detailed query,
+
+245
+00:20:11,000 --> 00:20:18,000
+because syntax of sequel is something you can always learn and something what you can always find on
+
+246
+00:20:18,000 --> 00:20:19,000
+the internet.
+
+247
+00:20:19,000 --> 00:20:27,000
+But deep understanding this assumption was belongs only to you and can be found in the internet.
+
+248
+00:20:27,000 --> 00:20:34,000
+So I suppose for a minute, if needed to understand this, once you feel sure that you understood this.
+
+249
+00:20:34,000 --> 00:20:35,000
+Let's proceed.
+
+250
+00:20:36,000 --> 00:20:43,000
+On the dining room, we usually mark this relationship with asterisk and one digit asterisk stands for
+
+251
+00:20:43,000 --> 00:20:44,000
+many.
+
+252
+00:20:44,000 --> 00:20:46,000
+And one stands for one.
+
+253
+00:20:47,000 --> 00:20:50,000
+Again, one user and many cars.
+
+254
+00:20:50,000 --> 00:20:52,000
+Each car has only one user.
+
+255
+00:20:53,000 --> 00:21:00,000
+One more thing in case you are going to use object, relational map and framework in your programming
+
+256
+00:21:00,000 --> 00:21:06,000
+language, you may find that sometimes there is a difference between one to many and many to one relationship.
+
+257
+00:21:07,000 --> 00:21:15,000
+Basically, these are the same relationship types, but the difference in what is read here in the current
+
+258
+00:21:15,000 --> 00:21:22,000
+object between the related other objects, for example, in the same case, relationship will be named
+
+259
+00:21:22,000 --> 00:21:30,000
+one to many in the user entity, and it will be managed to one incur entity do feel the difference.
+
+260
+00:21:31,000 --> 00:21:31,000
+That's great.
+
+261
+00:21:32,000 --> 00:21:32,000
+Let's move on.
+
+262
+00:21:34,000 --> 00:21:40,000
+And the next relationship that we are going to review today is managed to manage this kind of relationship
+
+263
+00:21:40,000 --> 00:21:47,000
+defiance as a situation when one records from one table may be connected to as many records from another
+
+264
+00:21:47,000 --> 00:21:52,000
+table and one records from another table may be connected to as many records from the first table.
+
+265
+00:21:53,000 --> 00:21:56,000
+I can say that many to many relationship.
+
+266
+00:21:56,000 --> 00:22:02,000
+It is also humans name, and technically this is just too one.
+
+267
+00:22:02,000 --> 00:22:07,000
+Too many relationships implemented in two directions doesn't make sense.
+
+268
+00:22:08,000 --> 00:22:11,000
+Let's try to understand how to implement this.
+
+269
+00:22:11,000 --> 00:22:14,000
+Imagine that we have students and different courses.
+
+270
+00:22:15,000 --> 00:22:22,000
+Each student may enroll in multiple courses, and basically each course may ask multiple students.
+
+271
+00:22:22,000 --> 00:22:30,000
+We have bidirectional one to many relationship between these two tables or, in other words, many too
+
+272
+00:22:30,000 --> 00:22:31,000
+many.
+
+273
+00:22:31,000 --> 00:22:39,000
+In this case, we can't just put foreign key into tables because we need to build many relationships
+
+274
+00:22:39,000 --> 00:22:45,000
+on one side and many relationships for each record on another side.
+
+275
+00:22:45,000 --> 00:22:50,000
+So technically, this is impossible to do with two tables only.
+
+276
+00:22:51,000 --> 00:22:56,000
+That's why to organize money into money relationships between two tables when it degrades a set table.
+
+277
+00:22:57,000 --> 00:23:05,000
+This table will contain foreign keys from one and the second tables and will map them between each other.
+
+278
+00:23:06,000 --> 00:23:13,000
+In this particular case, each student was I.D. one in the world, and some course we map these, of
+
+279
+00:23:13,000 --> 00:23:16,000
+course, and student in the SEC table.
+
+280
+00:23:16,000 --> 00:23:21,000
+And even this course has also students was I need to hand suite.
+
+281
+00:23:21,000 --> 00:23:25,000
+We also specify this in the table here.
+
+282
+00:23:25,000 --> 00:23:31,000
+We have Compound's primary key combination of these two fields has to be unique in each step.
+
+283
+00:23:32,000 --> 00:23:38,000
+Regarding naming convention for such tables, it depends on the final purpose of this table.
+
+284
+00:23:38,000 --> 00:23:45,000
+If we just want to establish connection between two entities, then we can use and the two names and
+
+285
+00:23:45,000 --> 00:23:48,000
+the verb that describes connection between them.
+
+286
+00:23:48,000 --> 00:23:56,000
+In this case, we can names a stable student has course or even should a student course, in case we
+
+287
+00:23:56,000 --> 00:24:04,000
+would add another business related info in each sample like date of enrollment, price information about
+
+288
+00:24:04,000 --> 00:24:09,000
+discounts and in case we're going to operate with this entity, as was a separate one.
+
+289
+00:24:10,000 --> 00:24:17,000
+In this case, we can give some business variable name to this table, for example, enrollment is that
+
+290
+00:24:17,000 --> 00:24:18,000
+clear.
+
+291
+00:24:19,000 --> 00:24:22,000
+And we have one more type of relationship to discuss.
+
+292
+00:24:23,000 --> 00:24:25,000
+I'm talking about one to one relationship.
+
+293
+00:24:25,000 --> 00:24:29,000
+This is the rarest type of relationship, to be honest.
+
+294
+00:24:29,000 --> 00:24:36,000
+Based on my experience, you would face was one too many and many, too many relationships more often
+
+295
+00:24:36,000 --> 00:24:38,000
+than was one to one.
+
+296
+00:24:38,000 --> 00:24:45,000
+Because this type of relationship describes very specific business case one one records in one table
+
+297
+00:24:45,000 --> 00:24:49,000
+is related with only one record from another table.
+
+298
+00:24:49,000 --> 00:24:52,000
+Can you think of cases like this?
+
+299
+00:24:52,000 --> 00:24:53,000
+It is hard to do.
+
+300
+00:24:53,000 --> 00:24:54,000
+Is that preparation?
+
+301
+00:24:55,000 --> 00:24:56,000
+And I can understand you.
+
+302
+00:24:57,000 --> 00:25:00,000
+I come up with some example for this type of relationship.
+
+303
+00:25:01,000 --> 00:25:06,000
+Imagine one transaction and you have table was all transactions in that.
+
+304
+00:25:07,000 --> 00:25:09,000
+And also there is transaction info table.
+
+305
+00:25:10,000 --> 00:25:13,000
+There is more detailed information about each transaction.
+
+306
+00:25:13,000 --> 00:25:19,000
+And it also stores sensitive information, and not all the users can read it.
+
+307
+00:25:19,000 --> 00:25:25,000
+That's why there is a need to store some attributes and values in secure table.
+
+308
+00:25:26,000 --> 00:25:32,000
+But still, there is a connection between these two tables, and each transaction is connected with
+
+309
+00:25:32,000 --> 00:25:36,000
+only one recording transaction in a table and vice versa.
+
+310
+00:25:37,000 --> 00:25:42,000
+Each transaction infrared connected to only one transaction.
+
+311
+00:25:42,000 --> 00:25:48,000
+To implement this connection, you can use two strategies you can use a use share key.
+
+312
+00:25:48,000 --> 00:25:56,000
+That means that the primary key in one table is equal to primary key in another table, or you can create
+
+313
+00:25:56,000 --> 00:26:02,000
+joint column and declare field where primary key will be exported in the table.
+
+314
+00:26:03,000 --> 00:26:09,000
+Most options are good in this case because they allow you to build the relationship between two tables.
+
+315
+00:26:10,000 --> 00:26:18,000
+I would just put a stress one more time on the fact that so many cases for one to one relationship heaven,
+
+316
+00:26:18,000 --> 00:26:24,000
+one to one relationship without clear argumentation is an indicator of pure database design.
+
+317
+00:26:25,000 --> 00:26:28,000
+That's all what I wanted to share with you in this lesson.
+
+318
+00:26:29,000 --> 00:26:36,000
+Now let's recap what we have learned today in this lesson of the grant basic terms in the relational
+
+319
+00:26:36,000 --> 00:26:37,000
+databases.
+
+320
+00:26:37,000 --> 00:26:43,000
+Now, you know the difference between such terms as database and schema you used in details of what
+
+321
+00:26:43,000 --> 00:26:45,000
+primary care is.
+
+322
+00:26:45,000 --> 00:26:52,000
+Also, we have learned different classifications of primary keys, such as single and compound, natural
+
+323
+00:26:52,000 --> 00:26:53,000
+and surrogate.
+
+324
+00:26:54,000 --> 00:26:59,000
+I explained to you what Ultimate Kit is after that.
+
+325
+00:26:59,000 --> 00:27:03,000
+We learned such an important concept in relational database as foreign key.
+
+326
+00:27:04,000 --> 00:27:08,000
+And at the end of the lesson, we've got three main types of relationship.
+
+327
+00:27:09,000 --> 00:27:15,000
+Now, you know the difference between one of the many, many too many and one to one relationships.
+
+328
+00:27:16,000 --> 00:27:17,000
+Thanks a lot for your attention, team.
+
+329
+00:27:18,000 --> 00:27:19,000
+Have a great day.
+
+330
+00:27:19,000 --> 00:27:20,000
+See you in the next lesson.
+

47 - Relational databases/002 Create Schema & Table Naming, Collation, Engines, Types, Column Properties_en.srt

@@ -0,0 +1,1888 @@
+1
+00:00:06,000 --> 00:00:07,000
+Hello came by this moment.
+
+2
+00:00:07,000 --> 00:00:12,000
+Now, of course, you already have some surgical knowledge about the relational databases.
+
+3
+00:00:12,000 --> 00:00:16,000
+And in this lesson, we're going to have more practice activities.
+
+4
+00:00:17,000 --> 00:00:22,000
+This lesson will be dedicated to learning of basic operations with database management system.
+
+5
+00:00:23,000 --> 00:00:26,000
+We are going to create schema and table in database.
+
+6
+00:00:26,000 --> 00:00:30,000
+And as we go, we'll learn a lot of interest in sinks.
+
+7
+00:00:31,000 --> 00:00:36,000
+We're going to have super interesting lessons because we'll start from practice activities.
+
+8
+00:00:36,000 --> 00:00:41,000
+And we're going to learn just enough series to achieve all of the lessons learned.
+
+9
+00:00:41,000 --> 00:00:44,000
+The lesson will perform operations in my school workbench.
+
+10
+00:00:44,000 --> 00:00:48,000
+And you will gradually start learning it step by step.
+
+11
+00:00:48,000 --> 00:00:54,000
+I would explain you what main buttons are and that will hold a live demo was explaining off each step
+
+12
+00:00:54,000 --> 00:00:55,000
+that I'm doing.
+
+13
+00:00:56,000 --> 00:01:02,000
+The main goal of the course in general and this lesson in particular, is orientation on skills that
+
+14
+00:01:02,000 --> 00:01:08,000
+you would need on practice and you already know enough theory to proceed with this lesson.
+
+15
+00:01:08,000 --> 00:01:15,000
+If you watched all previous lessons, now will not have one more serious lesson because I understand
+
+16
+00:01:15,000 --> 00:01:21,000
+that it will be hard to remember so much information without understanding how this information may
+
+17
+00:01:21,000 --> 00:01:22,000
+help you.
+
+18
+00:01:22,000 --> 00:01:25,000
+And why do you need to know it at all?
+
+19
+00:01:26,000 --> 00:01:31,000
+That's why in this lesson, we'll just create a schema and one table with you.
+
+20
+00:01:31,000 --> 00:01:37,000
+That's it sounds like not a lot of things to do, but still a lot of things to understand.
+
+21
+00:01:37,000 --> 00:01:40,000
+I will put separate focus on naming convention.
+
+22
+00:01:40,000 --> 00:01:43,000
+We'll talk about charset and collation.
+
+23
+00:01:43,000 --> 00:01:46,000
+Also, we are going to review my SQL storage engines.
+
+24
+00:01:47,000 --> 00:01:49,000
+One will start create columns in our table.
+
+25
+00:01:49,000 --> 00:01:53,000
+You will need to understand different data types and column properties.
+
+26
+00:01:54,000 --> 00:01:55,000
+Be prepared.
+
+27
+00:01:55,000 --> 00:01:58,000
+This is going to be interesting and useful lesson.
+
+28
+00:01:58,000 --> 00:01:59,000
+Let's start.
+
+29
+00:02:00,000 --> 00:02:02,000
+Let me start from the screen sharing straightaway.
+
+30
+00:02:03,000 --> 00:02:08,000
+As I already said, they were going to have a lot of practice activities in this lesson.
+
+31
+00:02:08,000 --> 00:02:10,000
+We're going to work in my school workbench.
+
+32
+00:02:10,000 --> 00:02:17,000
+In case you don't have neither my skill nor workbench installed, please refer to the previous lessons.
+
+33
+00:02:18,000 --> 00:02:24,000
+I have separate lesson where I explained how to install my school apps on your computer and configure
+
+34
+00:02:24,000 --> 00:02:26,000
+connection to my SQL server.
+
+35
+00:02:26,000 --> 00:02:35,000
+So here is how our connected server looks like we are my SQL workbench, he writes about interface once
+
+36
+00:02:35,000 --> 00:02:37,000
+connections within my SQL server is established.
+
+37
+00:02:37,000 --> 00:02:39,000
+You have a separate topic here.
+
+38
+00:02:40,000 --> 00:02:43,000
+You can return back on the home page if you wish.
+
+39
+00:02:43,000 --> 00:02:49,000
+By clicking on this icon and vice versa menu options are located here on top.
+
+40
+00:02:50,000 --> 00:02:54,000
+One of the most frequently used operations depicted, we are icons here.
+
+41
+00:02:55,000 --> 00:02:56,000
+We're going to use them and learn.
+
+42
+00:02:56,000 --> 00:02:58,000
+During the work was workbench.
+
+43
+00:02:58,000 --> 00:03:07,000
+Some of them are great SQL query, tap, create schema, create table inactive database, create a new
+
+44
+00:03:07,000 --> 00:03:09,000
+view and others.
+
+45
+00:03:09,000 --> 00:03:16,000
+Gradually, we'll have practice with each of these options potentially set in navigator view.
+
+46
+00:03:16,000 --> 00:03:20,000
+You have two taps, layer administration and schemas.
+
+47
+00:03:21,000 --> 00:03:27,000
+Since this is our first practical lesson, I wouldn't start from administration tab because I believe
+
+48
+00:03:27,000 --> 00:03:30,000
+we need to start from something more simple in this moment.
+
+49
+00:03:31,000 --> 00:03:37,000
+We're going to have also a separate lesson where I will explain how the administrator database, including
+
+50
+00:03:37,000 --> 00:03:43,000
+data imports and exports users and privileges configuration, server performance monitoring and others.
+
+51
+00:03:44,000 --> 00:03:51,000
+So in this lesson, let's perform our first steps in order to create our database and fill it out with
+
+52
+00:03:51,000 --> 00:03:51,000
+data.
+
+53
+00:03:52,000 --> 00:03:55,000
+The first thing that we need to do is to create schema.
+
+54
+00:03:56,000 --> 00:03:59,000
+Find this, I can hear it will help us to create schema.
+
+55
+00:04:00,000 --> 00:04:03,000
+We need to specify name of our schema.
+
+56
+00:04:03,000 --> 00:04:08,000
+Let's call it learning TDB and the first rule here.
+
+57
+00:04:08,000 --> 00:04:14,000
+While this is not a strict rule and you will grigg's a database, it is still strongly recommended to
+
+58
+00:04:14,000 --> 00:04:20,000
+follow the naming convention and naming convention is a set of unwritten rules.
+
+59
+00:04:20,000 --> 00:04:27,000
+We all should use if you want an increase in the ability of the whole data model will apply these rules
+
+60
+00:04:27,000 --> 00:04:35,000
+while naming A.I. inside the database tables, columns, primary and foreign keys, stored procedures,
+
+61
+00:04:35,000 --> 00:04:43,000
+functions, views, etc. While most rules are pretty logical, you could go with some you have invented
+
+62
+00:04:43,000 --> 00:04:45,000
+and that is completely up to you.
+
+63
+00:04:45,000 --> 00:04:52,000
+For example, when name any data be subject, it is recommended to use lower letters in case when you
+
+64
+00:04:52,000 --> 00:04:54,000
+to have multiple words and name.
+
+65
+00:04:54,000 --> 00:05:00,000
+We use underscore like in this case, for example, learn, underscore key.
+
+66
+00:05:00,000 --> 00:05:02,000
+Underscore me is a clear.
+
+67
+00:05:03,000 --> 00:05:10,000
+I believe that it is clear for you how to use Underscores, but probably the only one things that are
+
+68
+00:05:10,000 --> 00:05:16,000
+still not clear for you is why we need to follow naming convention and what benefits we expect to get.
+
+69
+00:05:16,000 --> 00:05:23,000
+For example, why we just can't follow the same naming convention as we have in Java and use camel case.
+
+70
+00:05:24,000 --> 00:05:27,000
+Let me name a few reasons to follow naming convention.
+
+71
+00:05:28,000 --> 00:05:28,000
+Reason number one.
+
+72
+00:05:29,000 --> 00:05:31,000
+Simplicity of the base model.
+
+73
+00:05:31,000 --> 00:05:35,000
+Usually, you don't have just one or two tables in your database.
+
+74
+00:05:36,000 --> 00:05:42,000
+Users are much more of them in your database, and having consistent naming would simplify navigation
+
+75
+00:05:42,000 --> 00:05:44,000
+between the tables and data.
+
+76
+00:05:44,000 --> 00:05:49,000
+Because to avoid total mass, you have to follow up this summer organizational rules.
+
+77
+00:05:49,000 --> 00:05:52,000
+The second reason is database stability.
+
+78
+00:05:52,000 --> 00:05:58,000
+If you decided to use the same naming convention as a programming language of your application, you
+
+79
+00:05:58,000 --> 00:06:04,000
+have to remember one more rule usually that the base is one of the most stable components in your app.
+
+80
+00:06:05,000 --> 00:06:09,000
+Changes and database layer one and only done with it is necessary.
+
+81
+00:06:10,000 --> 00:06:16,000
+Imagine that you would like to use Java naming convention for a database, but in one year you decided
+
+82
+00:06:16,000 --> 00:06:24,000
+to have other modules or even on loads of vital each, and those modules also interact with this database.
+
+83
+00:06:25,000 --> 00:06:26,000
+What will you do?
+
+84
+00:06:26,000 --> 00:06:33,000
+You can constantly change naming convention just because you changed main programming language in your
+
+85
+00:06:33,000 --> 00:06:35,000
+app that understands this.
+
+86
+00:06:36,000 --> 00:06:42,000
+In case you follow database naming convention, you can expect that even after you change the programming
+
+87
+00:06:42,000 --> 00:06:46,000
+language of your app, you still have stable database there.
+
+88
+00:06:47,000 --> 00:06:51,000
+This will help you to keep your database well, organized and structured.
+
+89
+00:06:52,000 --> 00:06:57,000
+And the last, but not the least reason with the ability of data monitoring by each team member.
+
+90
+00:06:57,000 --> 00:07:03,000
+Once you have specific paths that you follow, it will be easier for you and what is also important?
+
+91
+00:07:03,000 --> 00:07:07,000
+It would be easier for colleagues of yours to query a database.
+
+92
+00:07:07,000 --> 00:07:15,000
+What it often work Broken teams no small or big, and very often with support databases created not
+
+93
+00:07:15,000 --> 00:07:16,000
+by us.
+
+94
+00:07:16,000 --> 00:07:20,000
+That's why following common rules would simplify our lives.
+
+95
+00:07:21,000 --> 00:07:21,000
+Is that clear?
+
+96
+00:07:22,000 --> 00:07:28,000
+Even in case you still have any questions, please put your questions below this video, and I will
+
+97
+00:07:28,000 --> 00:07:30,000
+be happy to answer those.
+
+98
+00:07:31,000 --> 00:07:34,000
+So we specified name for our new schema.
+
+99
+00:07:34,000 --> 00:07:36,000
+What else we need to specify here?
+
+100
+00:07:36,000 --> 00:07:41,000
+Let's check together the next thing that we need to specify here.
+
+101
+00:07:41,000 --> 00:07:43,000
+I charset and collation.
+
+102
+00:07:43,000 --> 00:07:47,000
+Let's have you one by one and we'll start from Charset first.
+
+103
+00:07:48,000 --> 00:07:53,000
+And my second character set is a set of characters that are legal in a string.
+
+104
+00:07:53,000 --> 00:08:00,000
+For example, imagine that we have English alphabet from A to Z, and then we assign each letter to
+
+105
+00:08:00,000 --> 00:08:00,000
+a number.
+
+106
+00:08:00,000 --> 00:08:04,000
+We have a equal to one be equal to do and so on.
+
+107
+00:08:05,000 --> 00:08:07,000
+In this case, a is a symbol.
+
+108
+00:08:08,000 --> 00:08:15,000
+And number one that is associated with the letter A is encoded is a combination of all letters from
+
+109
+00:08:15,000 --> 00:08:20,000
+A to Z and Zach responding in accordance is a character set.
+
+110
+00:08:20,000 --> 00:08:21,000
+This makes sense.
+
+111
+00:08:22,000 --> 00:08:25,000
+Can you understand now what the charset is?
+
+112
+00:08:25,000 --> 00:08:30,000
+Let's select in charset UTF eight and B for?
+
+113
+00:08:31,000 --> 00:08:37,000
+Because we need Typekit UTF eight and coding sets use for bytes to store character.
+
+114
+00:08:37,000 --> 00:08:46,000
+By default, most people use UTF eight as Alice off UTF eight and B three is its only source and maximum
+
+115
+00:08:46,000 --> 00:08:48,000
+of three bytes per quarter point.
+
+116
+00:08:49,000 --> 00:08:54,000
+On the official website of my school, it is referred as deprecated and it is mentioned that it will
+
+117
+00:08:54,000 --> 00:08:55,000
+be removed.
+
+118
+00:08:55,000 --> 00:09:03,000
+Instead, it is recommended to use UTF eight and B for each character set has one or more correlations.
+
+119
+00:09:03,000 --> 00:09:04,000
+Is it defined?
+
+120
+00:09:04,000 --> 00:09:10,000
+A set of rules for comparing characters within the character set and my school collation is a set of
+
+121
+00:09:10,000 --> 00:09:14,000
+rules used to compare characters in the particular character.
+
+122
+00:09:14,000 --> 00:09:21,000
+Set each character set in my school as at least one default collation, and it can have more than one
+
+123
+00:09:21,000 --> 00:09:22,000
+collation.
+
+124
+00:09:23,000 --> 00:09:29,000
+However, the character sets cannot have the same collation, usually as there is a default collation
+
+125
+00:09:29,000 --> 00:09:32,000
+associated with each other set.
+
+126
+00:09:32,000 --> 00:09:39,000
+But during the creation of our schema, we can select a collation for our charset by convention.
+
+127
+00:09:40,000 --> 00:09:45,000
+Collation for a current set begins with the character, set name and ends with.
+
+128
+00:09:46,000 --> 00:09:55,000
+As I just stands for case insensitive, CSA stands for case sensitive or being as it stands for binary.
+
+129
+00:09:56,000 --> 00:10:04,000
+My school allows you to specify a character set and collation at levels server, database, table and
+
+130
+00:10:04,000 --> 00:10:04,000
+column.
+
+131
+00:10:05,000 --> 00:10:11,000
+Currently, we can set up collation and database level, and if you are wondering which collation to
+
+132
+00:10:11,000 --> 00:10:19,000
+choose, I recommend you to go with UTF rmv for Unicode psi so that sorting is always handled properly.
+
+133
+00:10:19,000 --> 00:10:22,000
+It was minimal and noticeable performance drawbacks.
+
+134
+00:10:23,000 --> 00:10:29,000
+Anyway, you can see there are really a lot of different variations of collation here, and you can
+
+135
+00:10:29,000 --> 00:10:35,000
+check documentation to select the ones that works best for you in case you're also experiencing issues.
+
+136
+00:10:35,000 --> 00:10:41,000
+Was interface here like I do, and you can see the whole name of just selection.
+
+137
+00:10:41,000 --> 00:10:42,000
+Don't worry.
+
+138
+00:10:42,000 --> 00:10:48,000
+In my school revenge area operations that you are going to perform, this translates into SQL quick
+
+139
+00:10:49,000 --> 00:10:52,000
+and you can check query before execution of any command.
+
+140
+00:10:53,000 --> 00:10:57,000
+By the way, this is also one of the ways to learn sequel better.
+
+141
+00:10:58,000 --> 00:11:02,000
+I click a plain button here and here you can see SQL query.
+
+142
+00:11:02,000 --> 00:11:04,000
+This is not the lesson about a sequel.
+
+143
+00:11:05,000 --> 00:11:11,000
+My goal was to let you understand what operations we need and we can do in general.
+
+144
+00:11:11,000 --> 00:11:15,000
+Our database and only after that jump to none in the sequel.
+
+145
+00:11:15,000 --> 00:11:20,000
+Because when I started learning SQL School with students straight away, they just couldn't understand
+
+146
+00:11:20,000 --> 00:11:23,000
+why they need this and what they're doing with it.
+
+147
+00:11:24,000 --> 00:11:31,000
+As you can see here, we use great operator to create schema with name 90 DB with default character
+
+148
+00:11:31,000 --> 00:11:36,000
+set UTF eight and before and collation UTF eight and before in the courtyard.
+
+149
+00:11:37,000 --> 00:11:44,000
+Even in case you select the wrong option because you were not able to use a full name and drop down.
+
+150
+00:11:45,000 --> 00:11:47,000
+You can adjust name of collation here.
+
+151
+00:11:48,000 --> 00:11:50,000
+Now, query looks good to me.
+
+152
+00:11:50,000 --> 00:11:51,000
+That's executed.
+
+153
+00:11:52,000 --> 00:11:58,000
+In case operation was successful, you can see a sequel statement has been executed successfully.
+
+154
+00:11:58,000 --> 00:12:03,000
+Click Finish Button now on Sikkema Step on the left.
+
+155
+00:12:03,000 --> 00:12:06,000
+We can see that we have a new schema in the list here.
+
+156
+00:12:07,000 --> 00:12:13,000
+Nemo Creek was mouse left click and once the name of the database is in bold, that means you selected
+
+157
+00:12:13,000 --> 00:12:16,000
+the specific database and you can work with it.
+
+158
+00:12:17,000 --> 00:12:22,000
+Inside, you can see that we may have tables, views, stored procedures, functions.
+
+159
+00:12:23,000 --> 00:12:28,000
+We are going to learn how to create all these database objects and how to work with them.
+
+160
+00:12:28,000 --> 00:12:33,000
+But in this lesson, let's create table and perform basic operations with it.
+
+161
+00:12:34,000 --> 00:12:38,000
+We can create table people using the workbench interface in different ways.
+
+162
+00:12:38,000 --> 00:12:45,000
+You can use one of the many items here is at the school to create new table or you can use menu.
+
+163
+00:12:46,000 --> 00:12:50,000
+I do mouse right click on tables and select Create Table.
+
+164
+00:12:51,000 --> 00:12:54,000
+Let me walk you through the configuration here.
+
+165
+00:12:55,000 --> 00:12:59,000
+The first thing we need to specify here is stable name.
+
+166
+00:12:59,000 --> 00:13:06,000
+Let's imagine that we want to create user table user table will contain information about users.
+
+167
+00:13:06,000 --> 00:13:10,000
+And now we're in sync about naming convention for tables.
+
+168
+00:13:11,000 --> 00:13:17,000
+One of the arguable questions is whether you need to use plural and the naming of tables or singular.
+
+169
+00:13:17,000 --> 00:13:24,000
+For example, if you're going to store users in this table, isn't it logical to name table users in
+
+170
+00:13:24,000 --> 00:13:24,000
+plural?
+
+171
+00:13:25,000 --> 00:13:27,000
+So different points of view on this?
+
+172
+00:13:28,000 --> 00:13:28,000
+Let me explain.
+
+173
+00:13:30,000 --> 00:13:33,000
+The first option is to use Singapore four table name.
+
+174
+00:13:33,000 --> 00:13:35,000
+That is what I would recommend you to.
+
+175
+00:13:36,000 --> 00:13:41,000
+I prefer to use the uninfected noun, which in English happens to be singular.
+
+176
+00:13:42,000 --> 00:13:48,000
+If your name and entities that represent real world facts, you should use nouns.
+
+177
+00:13:49,000 --> 00:13:54,000
+These are tables like employee, customer, city and country, for example.
+
+178
+00:13:55,000 --> 00:14:00,000
+If possible, use a single word that exactly describes what is in the table.
+
+179
+00:14:01,000 --> 00:14:05,000
+Let's try to understand what benefits this brings to us.
+
+180
+00:14:05,000 --> 00:14:12,000
+The first reason is logical and semantic, and really understands that this is also maybe considered
+
+181
+00:14:12,000 --> 00:14:13,000
+as arguable point.
+
+182
+00:14:14,000 --> 00:14:21,000
+For example, at your home, if you have back with socks, you would put a label on it that says sucks,
+
+183
+00:14:22,000 --> 00:14:24,000
+but not Sock and Single-A.
+
+184
+00:14:24,000 --> 00:14:29,000
+But another question why you should apply naming convention from socks to a database?
+
+185
+00:14:30,000 --> 00:14:30,000
+Just joking.
+
+186
+00:14:30,000 --> 00:14:37,000
+But indeed, naming people in plural form also contains some logical hosts, because if you want to
+
+187
+00:14:37,000 --> 00:14:42,000
+name people in plural, why would don't ask us questions about grammar too?
+
+188
+00:14:43,000 --> 00:14:49,000
+For example, we also might be thinking about questions like this, since we're usually doing something
+
+189
+00:14:49,000 --> 00:14:50,000
+with zeros.
+
+190
+00:14:50,000 --> 00:14:55,000
+Why not to put the name in the accusative case or another question?
+
+191
+00:14:55,000 --> 00:15:03,000
+If we have a tables that will write to laws and we agree, why not put the name indeed, if it is table
+
+192
+00:15:03,000 --> 00:15:04,000
+of Simpson?
+
+193
+00:15:04,000 --> 00:15:06,000
+Why not use genitive?
+
+194
+00:15:07,000 --> 00:15:07,000
+And you know what?
+
+195
+00:15:08,000 --> 00:15:12,000
+We will not constantly address all of these questions because we will end up with a mess.
+
+196
+00:15:13,000 --> 00:15:15,000
+The table is defined as an abstract.
+
+197
+00:15:15,000 --> 00:15:20,000
+Content exists regardless of its state or usage uses.
+
+198
+00:15:20,000 --> 00:15:26,000
+An unaffected noun is simple, logical, regular and language independent.
+
+199
+00:15:27,000 --> 00:15:28,000
+The second reason is convenience.
+
+200
+00:15:29,000 --> 00:15:32,000
+It is easy to come out with a single names.
+
+201
+00:15:32,000 --> 00:15:33,000
+Xen was plural.
+
+202
+00:15:33,000 --> 00:15:41,000
+Once objects can have irregular plurals, are not normal at all, but will always have a single one.
+
+203
+00:15:41,000 --> 00:15:43,000
+With few exceptions like news.
+
+204
+00:15:44,000 --> 00:15:46,000
+Another reason is simplicity.
+
+205
+00:15:46,000 --> 00:15:51,000
+One little gem to learn in the sequel, you are going to use table names for queries.
+
+206
+00:15:51,000 --> 00:15:58,000
+Also, we're going to refer to attributes of a table like, for example, to get the value of name attributes
+
+207
+00:15:58,000 --> 00:15:58,000
+and use.
+
+208
+00:15:58,000 --> 00:16:04,000
+Our table will use user not name, but not users, not name.
+
+209
+00:16:04,000 --> 00:16:07,000
+And it seems logical and simple.
+
+210
+00:16:07,000 --> 00:16:08,000
+Don't you think so?
+
+211
+00:16:08,000 --> 00:16:13,000
+You extract the name of specific user, but not all users.
+
+212
+00:16:14,000 --> 00:16:14,000
+Definitely.
+
+213
+00:16:14,000 --> 00:16:19,000
+I can find the workarounds for these two more experienced students.
+
+214
+00:16:19,000 --> 00:16:24,000
+While watching this video may mention that we can use Alliss for table names.
+
+215
+00:16:24,000 --> 00:16:26,000
+But why we need to do this?
+
+216
+00:16:26,000 --> 00:16:29,000
+You could just can name table in singular.
+
+217
+00:16:29,000 --> 00:16:29,000
+And that's it.
+
+218
+00:16:30,000 --> 00:16:35,000
+I'm the guy who always finds a way to simplify everything to the possible degree.
+
+219
+00:16:35,000 --> 00:16:37,000
+And this is one of the cases.
+
+220
+00:16:37,000 --> 00:16:43,000
+One more reason is that often consider it's not like an important one, but still it's worth of your
+
+221
+00:16:43,000 --> 00:16:43,000
+attention.
+
+222
+00:16:44,000 --> 00:16:45,000
+It is globalization.
+
+223
+00:16:45,000 --> 00:16:51,000
+We often work in multinational teams, and we're often for many of team members.
+
+224
+00:16:51,000 --> 00:16:58,000
+English is not native language and having a repository table instead of repositories or having status
+
+225
+00:16:58,000 --> 00:17:00,000
+table instead of statuses.
+
+226
+00:17:00,000 --> 00:17:07,000
+We'll save your team a lot of time and minimize errors because of typos and similar linguistic issues.
+
+227
+00:17:07,000 --> 00:17:13,000
+Probably this is not like the most critical reason to use single names for tables.
+
+228
+00:17:13,000 --> 00:17:15,000
+But promise me just to think about it.
+
+229
+00:17:16,000 --> 00:17:23,000
+And that's a point to think about, you know, the table names may consist of multiple words separated
+
+230
+00:17:23,000 --> 00:17:27,000
+by underscore this would raise additional questions from your team.
+
+231
+00:17:27,000 --> 00:17:30,000
+What words should be in plural and which not?
+
+232
+00:17:31,000 --> 00:17:37,000
+For example, or the detail if you use single zone, no questions at all.
+
+233
+00:17:37,000 --> 00:17:42,000
+It is simple to write queries because you remember that everything isn't singular.
+
+234
+00:17:43,000 --> 00:17:46,000
+But in case you would like to follow some grammar, how far will you go?
+
+235
+00:17:47,000 --> 00:17:54,000
+Really use all the details or some key members, many things that you should name this table as order
+
+236
+00:17:54,000 --> 00:17:55,000
+details.
+
+237
+00:17:55,000 --> 00:18:01,000
+Believe me, this might happen and this will happen in big multinational team, and they give you a
+
+238
+00:18:01,000 --> 00:18:05,000
+chance to think about it right now before you start that new project.
+
+239
+00:18:06,000 --> 00:18:10,000
+And always remember the tables are the subjects of the database.
+
+240
+00:18:10,000 --> 00:18:14,000
+Thus, they announce again, Single-A.
+
+241
+00:18:15,000 --> 00:18:21,000
+There might be different reasons to use single for table names, but in my opinion, these are the most
+
+242
+00:18:21,000 --> 00:18:21,000
+important ones.
+
+243
+00:18:22,000 --> 00:18:23,000
+I wouldn't like to use that.
+
+244
+00:18:23,000 --> 00:18:30,000
+I always worked on the projects where tables were named as singular, sometimes so rotten project where
+
+245
+00:18:30,000 --> 00:18:36,000
+we use plural for database tables, names and remember the main sink in.
+
+246
+00:18:36,000 --> 00:18:38,000
+Each naming convention is consistency.
+
+247
+00:18:39,000 --> 00:18:44,000
+The whole team agreed to follow some specific naming convention and different generation of programmers.
+
+248
+00:18:44,000 --> 00:18:50,000
+Since this project also understands this and agreed with this, then you don't have any problem at all.
+
+249
+00:18:50,000 --> 00:18:56,000
+And then comes a day your team might find logical the name container or froze with plural if container
+
+250
+00:18:56,000 --> 00:18:58,000
+contains users.
+
+251
+00:18:58,000 --> 00:19:05,000
+It is obvious that we have to name it users, but we also reviewed point of use that explains why this
+
+252
+00:19:05,000 --> 00:19:08,000
+might not always be the best way to name a table.
+
+253
+00:19:09,000 --> 00:19:14,000
+To be honest, it is hard for me to come up with other advantages of using plural names for tables.
+
+254
+00:19:15,000 --> 00:19:19,000
+Remember, it is always up to you what naming convention you are going to follow.
+
+255
+00:19:20,000 --> 00:19:26,000
+But the most important here is consistency in naming across different parts of your app.
+
+256
+00:19:26,000 --> 00:19:32,000
+I believe I answer to all concerns regarding the naming convention and why I named the bill in singular
+
+257
+00:19:32,000 --> 00:19:33,000
+form.
+
+258
+00:19:33,000 --> 00:19:34,000
+Let's proceed.
+
+259
+00:19:34,000 --> 00:19:40,000
+So you already know that you can set charset and collation on table level two.
+
+260
+00:19:40,000 --> 00:19:44,000
+Another interesting configuration here is an engine.
+
+261
+00:19:44,000 --> 00:19:45,000
+Let's talk about it now.
+
+262
+00:19:46,000 --> 00:19:50,000
+Let me explain you more about search engines in my school.
+
+263
+00:19:50,000 --> 00:19:57,000
+The search engine is a software module that database management system uses for me operations with data
+
+264
+00:19:58,000 --> 00:20:00,000
+such as Create, Read, Update, Delete.
+
+265
+00:20:01,000 --> 00:20:08,000
+Generally speaking, there are two types of storage engines in my school transactional and non transactional.
+
+266
+00:20:08,000 --> 00:20:11,000
+In my school, we have nine types of storage engines.
+
+267
+00:20:12,000 --> 00:20:15,000
+Two campuses was a school bus.
+
+268
+00:20:15,000 --> 00:20:17,000
+With schools, there's one storage engine.
+
+269
+00:20:18,000 --> 00:20:24,000
+It is very important to select the right search engine because this is strategic decision that will
+
+270
+00:20:24,000 --> 00:20:25,000
+impact future development.
+
+271
+00:20:25,000 --> 00:20:32,000
+The default search engine in my school is in the B from version five point five and later.
+
+272
+00:20:32,000 --> 00:20:34,000
+Previously, it was my is some.
+
+273
+00:20:35,000 --> 00:20:38,000
+Let me very briefly cover each storage engine in order.
+
+274
+00:20:38,000 --> 00:20:40,000
+You could understand the difference.
+
+275
+00:20:41,000 --> 00:20:46,000
+In a debate is the most widely used storage engine with transaction support.
+
+276
+00:20:46,000 --> 00:20:53,000
+It is an acid compliant storage engine as it compliant means it meets requirements for transactions
+
+277
+00:20:54,000 --> 00:20:59,000
+as it is an acronym that stands for atomic consistent, independent, durable.
+
+278
+00:21:00,000 --> 00:21:04,000
+These are properties of transactions that we are going to cover in detail.
+
+279
+00:21:04,000 --> 00:21:11,000
+A lesson about transactions in a the B supports roll level locking crash recovery and motivation version
+
+280
+00:21:11,000 --> 00:21:13,000
+concurrency control.
+
+281
+00:21:13,000 --> 00:21:18,000
+It is the only engine which provides foreign key, referential integrity constrained.
+
+282
+00:21:19,000 --> 00:21:26,000
+Oracle recommends using Unity B for tables except for specialized use cases, and thus the search engine
+
+283
+00:21:26,000 --> 00:21:27,000
+is my is.
+
+284
+00:21:27,000 --> 00:21:31,000
+The main difference from Inada be it is not transactional one.
+
+285
+00:21:32,000 --> 00:21:34,000
+It is a relatively fast storage engine.
+
+286
+00:21:35,000 --> 00:21:39,000
+But as we already said, it doesn't support transactions.
+
+287
+00:21:39,000 --> 00:21:42,000
+My ISA provides stable level locking.
+
+288
+00:21:42,000 --> 00:21:45,000
+It is used mostly in lab and data warehousing.
+
+289
+00:21:46,000 --> 00:21:49,000
+Let me say now a few words about memory storage engine.
+
+290
+00:21:50,000 --> 00:21:56,000
+It is named, so because it creates tables in memory, it is the fastest engine.
+
+291
+00:21:56,000 --> 00:21:58,000
+It provides stable level locking.
+
+292
+00:21:59,000 --> 00:22:01,000
+It doesn't support transactions.
+
+293
+00:22:01,000 --> 00:22:06,000
+Memory storage engine is ideal for creating temporary tables or quick look ups.
+
+294
+00:22:07,000 --> 00:22:10,000
+The data is lost when the database is restarted.
+
+295
+00:22:10,000 --> 00:22:16,000
+Different news There are not so many use cases for the search engine because each application requires
+
+296
+00:22:16,000 --> 00:22:17,000
+persistent storage.
+
+297
+00:22:18,000 --> 00:22:21,000
+See, a Swiss storage engine has specific formats of the stored data.
+
+298
+00:22:22,000 --> 00:22:24,000
+It stores data in CSP files.
+
+299
+00:22:24,000 --> 00:22:31,000
+It provides great flexibility because data in this format is easily integrated into other applications.
+
+300
+00:22:31,000 --> 00:22:35,000
+Match operates on underlying might e some tables.
+
+301
+00:22:35,000 --> 00:22:39,000
+Match tables help manage large volume of data more easily.
+
+302
+00:22:40,000 --> 00:22:46,000
+It logically groups a series of identical might use some tables and references them as one object.
+
+303
+00:22:46,000 --> 00:22:53,000
+Good for data warehousing environments Archive search engine is optimized for high speed and certain
+
+304
+00:22:54,000 --> 00:22:56,000
+it compresses data as it is inserted.
+
+305
+00:22:57,000 --> 00:22:59,000
+It doesn't support transactions.
+
+306
+00:22:59,000 --> 00:23:07,000
+It is a yield for storing and retrieving large amounts of seldom referenced historical archive data.
+
+307
+00:23:08,000 --> 00:23:14,000
+The black hole search engine accepts but doesn't store data which reveals always written and them to
+
+308
+00:23:14,000 --> 00:23:16,000
+set critical feature.
+
+309
+00:23:16,000 --> 00:23:17,000
+Don't you think so?
+
+310
+00:23:17,000 --> 00:23:18,000
+And I understand your feeling.
+
+311
+00:23:19,000 --> 00:23:25,000
+Probably it is not so easy to come up with the use case for such storing engine, but I have few use
+
+312
+00:23:25,000 --> 00:23:28,000
+cases when this might come in handy.
+
+313
+00:23:28,000 --> 00:23:34,000
+The French analogy can be used in distributed database design, where data is automatically replicated
+
+314
+00:23:34,000 --> 00:23:37,000
+but not stored locally and also does.
+
+315
+00:23:37,000 --> 00:23:42,000
+This search engine can be used to execute performance tests or other testing.
+
+316
+00:23:43,000 --> 00:23:49,000
+Federated Search Engine offers the ability to separate my Secret Service to create one logical database
+
+317
+00:23:49,000 --> 00:23:51,000
+from many physical service.
+
+318
+00:23:51,000 --> 00:23:57,000
+Queries on the local server are automatically executed on the remote federated tables.
+
+319
+00:23:57,000 --> 00:24:00,000
+No data is stored on the local tables.
+
+320
+00:24:00,000 --> 00:24:07,000
+It is good for distributed environments, and the B cluster is an in-memory storage engine, offering
+
+321
+00:24:07,000 --> 00:24:10,000
+high availability and data persistence features.
+
+322
+00:24:11,000 --> 00:24:18,000
+The engine cluster storage engine can be configured with a range or fail over and load balancing options.
+
+323
+00:24:18,000 --> 00:24:25,000
+Using SQL notes is the most common way of executing queries, and SQL note is the same as an instance
+
+324
+00:24:25,000 --> 00:24:33,000
+of my SQL server was the NDB storage engine compiled in the NDB search engine provides a breach from
+
+325
+00:24:33,000 --> 00:24:34,000
+my SQL server.
+
+326
+00:24:34,000 --> 00:24:41,000
+List of data nodes and DB search engine is implemented using a distributed shared nutzen architecture,
+
+327
+00:24:42,000 --> 00:24:47,000
+which causes it to behave differently from anybody b in a number of ways.
+
+328
+00:24:47,000 --> 00:24:55,000
+For those unaccustomed to work and was NDB, unexpected behaviors can arise is distributed nature with
+
+329
+00:24:55,000 --> 00:25:01,000
+regard to transactions for in case table limits and other characteristics.
+
+330
+00:25:01,000 --> 00:25:07,000
+This is not so easy to explain in a few sentences, but in general, if you are interested, you can
+
+331
+00:25:07,000 --> 00:25:12,000
+ask is a specific question about the search engine or find documentation on my SQL side.
+
+332
+00:25:13,000 --> 00:25:17,000
+So what search engine to choose among such variety?
+
+333
+00:25:17,000 --> 00:25:23,000
+It depends on the up to you and business problem you are trying to address and once saying you should
+
+334
+00:25:23,000 --> 00:25:29,000
+remember for sure, there is no perfect search engine littered with works the best in all possible cases.
+
+335
+00:25:29,000 --> 00:25:35,000
+Some of them better under certain conditions and perform worse in other situations, and some of them
+
+336
+00:25:35,000 --> 00:25:36,000
+vice versa.
+
+337
+00:25:37,000 --> 00:25:41,000
+In software engineering, it is always a matter of tradeoffs and.
+
+338
+00:25:41,000 --> 00:25:43,000
+Most secure solution takes more resources.
+
+339
+00:25:44,000 --> 00:25:48,000
+Thus, it might be slower, take more CPU time and disk space.
+
+340
+00:25:49,000 --> 00:25:54,000
+But you should understand that you have not one but nine storage engines.
+
+341
+00:25:54,000 --> 00:26:00,000
+And my sequel is very flexible in the fact that it provides several different storage engines.
+
+342
+00:26:00,000 --> 00:26:05,000
+Some of them, like archive engine, are created to be used in specific situations.
+
+343
+00:26:06,000 --> 00:26:13,000
+In some cases, the answer is clear whenever we're dealing with some payment systems, we are obligated
+
+344
+00:26:13,000 --> 00:26:15,000
+to use the transactional storage.
+
+345
+00:26:15,000 --> 00:26:21,000
+We cannot afford to lose such sensitive data in a debate is the way to go.
+
+346
+00:26:22,000 --> 00:26:27,000
+If we want full text search, then we can choose is a mighty sum or in the be.
+
+347
+00:26:28,000 --> 00:26:33,000
+Now, you know, the difference between different storage engines in our particular case.
+
+348
+00:26:33,000 --> 00:26:38,000
+Let's keep the default one here, so I keep an eye on the Beast search engine.
+
+349
+00:26:38,000 --> 00:26:41,000
+After that, we can proceed with declaring columns.
+
+350
+00:26:41,000 --> 00:26:42,000
+Let's use surrogate.
+
+351
+00:26:42,000 --> 00:26:48,000
+Primary key was name I.D. for each row, and let's make it of type in.
+
+352
+00:26:49,000 --> 00:26:53,000
+You have to fill out column name, data type and set column properties.
+
+353
+00:26:54,000 --> 00:26:59,000
+We are going to learn more about each column property right after we finish a discussion about data
+
+354
+00:26:59,000 --> 00:26:59,000
+types.
+
+355
+00:27:00,000 --> 00:27:06,000
+As you see, each column will have its own data type, then different types and different relational
+
+356
+00:27:06,000 --> 00:27:11,000
+database management systems, but more or less this similar in my cycle.
+
+357
+00:27:11,000 --> 00:27:19,000
+All data types might be grouped into the next categories numeric data types date and time data types
+
+358
+00:27:20,000 --> 00:27:29,000
+string data types spatial data types My circle supports geometry types of point lines, string, polygon
+
+359
+00:27:29,000 --> 00:27:37,000
+multipoint, multi-line string, multi polygon and Geometry Collection OSR geometry types are not supported.
+
+360
+00:27:38,000 --> 00:27:44,000
+JSON data type most likely will not go over each and every possible data type.
+
+361
+00:27:44,000 --> 00:27:52,000
+In my school, I prepared slides to cover the most popular numeric date and time and string data types.
+
+362
+00:27:53,000 --> 00:27:59,000
+On this slide, you can find numeric data types, I suppose, for a minute if you want to read comments
+
+363
+00:27:59,000 --> 00:28:05,000
+for each particular data type here, but in most cases you are going to use and type.
+
+364
+00:28:06,000 --> 00:28:09,000
+That is my opinion, probably sometimes.
+
+365
+00:28:09,000 --> 00:28:11,000
+So I'm going to use other data types too.
+
+366
+00:28:11,000 --> 00:28:19,000
+But in time is generally enough, especially if we use unsigned and you have one more additional beat
+
+367
+00:28:19,000 --> 00:28:26,000
+to store information and attention in this list, you have both integers and floating point numbers,
+
+368
+00:28:26,000 --> 00:28:32,000
+so you can select data type for your columns that meets business needs to store value.
+
+369
+00:28:32,000 --> 00:28:40,000
+On this slide, you can find data types that will help you to represent date and time in database humorists
+
+370
+00:28:40,000 --> 00:28:47,000
+or date or time separately, or you can store data time looking with date and time.
+
+371
+00:28:47,000 --> 00:28:49,000
+And what original app always was a patent?
+
+372
+00:28:50,000 --> 00:28:50,000
+Why?
+
+373
+00:28:51,000 --> 00:28:58,000
+First of all, for Martin, during the storm and database and retrieved from database, it seems to
+
+374
+00:28:58,000 --> 00:28:59,000
+be like a simple scene.
+
+375
+00:28:59,000 --> 00:29:06,000
+But I promise you, at least someone from your team will mess up was for the second things that might
+
+376
+00:29:06,000 --> 00:29:08,000
+be challenging time zones.
+
+377
+00:29:09,000 --> 00:29:12,000
+Team, believe me, time zones are very, very painful.
+
+378
+00:29:13,000 --> 00:29:20,000
+Some engineers use time stamp to store a number of seconds since Unix epoch, but there is a specific
+
+379
+00:29:20,000 --> 00:29:23,000
+range of data that is supported by my SQL by default.
+
+380
+00:29:23,000 --> 00:29:30,000
+So one of us options, probably it is not super duper popular, but still look around.
+
+381
+00:29:30,000 --> 00:29:31,000
+It deserves to leave.
+
+382
+00:29:32,000 --> 00:29:40,000
+You can use even in data types to serve milliseconds from Unix epoch heaven, time and milliseconds.
+
+383
+00:29:40,000 --> 00:29:46,000
+You can convert it in any app any day during the conversion in both direction.
+
+384
+00:29:46,000 --> 00:29:48,000
+You can consider time zone of the user.
+
+385
+00:29:49,000 --> 00:29:53,000
+In this case, all milliseconds would be according to UTC.
+
+386
+00:29:53,000 --> 00:29:56,000
+The Understand what I'm talking about.
+
+387
+00:29:56,000 --> 00:29:58,000
+Remember this workaround?
+
+388
+00:29:58,000 --> 00:30:03,000
+It might help you some day and no matter what application you will work with.
+
+389
+00:30:03,000 --> 00:30:09,000
+And also, if you want to learn more about date and time in Java, please refer to my Java course.
+
+390
+00:30:09,000 --> 00:30:15,000
+I have separate lessons, dedicated time zones and working with date and time in Java programs.
+
+391
+00:30:15,000 --> 00:30:21,000
+And on this slide, you can see a list of data types that you can use to store text values.
+
+392
+00:30:21,000 --> 00:30:27,000
+One of the differences between all these types is amount of memory that is reserved to stores.
+
+393
+00:30:27,000 --> 00:30:33,000
+The value in this field bressan course if you want to check comments for each day that that.
+
+394
+00:30:34,000 --> 00:30:37,000
+So we learned what data types might be used for columns.
+
+395
+00:30:38,000 --> 00:30:40,000
+Now let's learn another thing.
+
+396
+00:30:40,000 --> 00:30:42,000
+Let's talk about column properties.
+
+397
+00:30:43,000 --> 00:30:45,000
+You can see different letters here.
+
+398
+00:30:45,000 --> 00:30:49,000
+And also the checkbox here they are the same.
+
+399
+00:30:50,000 --> 00:30:52,000
+Let's learn what those they meant.
+
+400
+00:30:53,000 --> 00:30:59,000
+K stands for primary key and N stands for Not Now You.
+
+401
+00:30:59,000 --> 00:31:01,000
+Q stands for unique.
+
+402
+00:31:01,000 --> 00:31:03,000
+This creates unique index.
+
+403
+00:31:03,000 --> 00:31:06,000
+We're going to learn about indexes in the separate lesson.
+
+404
+00:31:07,000 --> 00:31:10,000
+B stands for binary stores data as binary strings.
+
+405
+00:31:11,000 --> 00:31:18,000
+There is no character set so certain, and comparison is based on the numerical values of the bytes
+
+406
+00:31:18,000 --> 00:31:21,000
+in the values you and stands for.
+
+407
+00:31:21,000 --> 00:31:21,000
+And.
+
+408
+00:31:22,000 --> 00:31:27,000
+That is property for all no data types that allows you to store only positive numbers.
+
+409
+00:31:28,000 --> 00:31:30,000
+ZF stands for zero field.
+
+410
+00:31:30,000 --> 00:31:32,000
+This is an interesting one.
+
+411
+00:31:32,000 --> 00:31:39,000
+I need to demo this will use zero field property for one of the fields just in demo purposes.
+
+412
+00:31:39,000 --> 00:31:44,000
+In short, it feels with zero all the lengths reserved for value.
+
+413
+00:31:44,000 --> 00:31:47,000
+Eight AI stands for auto increment.
+
+414
+00:31:47,000 --> 00:31:50,000
+No value can be increased by one.
+
+415
+00:31:50,000 --> 00:31:55,000
+Usually, this one is used for surrogate primary keys in order that the base can generate unique number
+
+416
+00:31:55,000 --> 00:32:05,000
+for ID field by increment in values with each new record inserted and G stands for generated, the value
+
+417
+00:32:05,000 --> 00:32:09,000
+is generated by a formula based on other columns.
+
+418
+00:32:10,000 --> 00:32:17,000
+If the field is primary key, that means that this field will have only unique values, not new values.
+
+419
+00:32:17,000 --> 00:32:21,000
+Additionally, I recommend you to at all to increment property.
+
+420
+00:32:21,000 --> 00:32:27,000
+This will automatically increment your I.D. integer value on each new insertion.
+
+421
+00:32:28,000 --> 00:32:30,000
+In this case, you shouldn't be to.
+
+422
+00:32:30,000 --> 00:32:32,000
+It's a generation of unique I.D..
+
+423
+00:32:33,000 --> 00:32:39,000
+Also, I want to use unsigned integer values in order to increase range of positive numbers that can
+
+424
+00:32:39,000 --> 00:32:40,000
+be used as I.D..
+
+425
+00:32:41,000 --> 00:32:44,000
+Let's also create a few more fields of virtual time.
+
+426
+00:32:45,000 --> 00:32:50,000
+We're going to create first name, last name and email to create each new field.
+
+427
+00:32:50,000 --> 00:32:53,000
+Just press on empty space.
+
+428
+00:32:55,000 --> 00:33:02,000
+I will create unique index for email column to make performance of extract any user by email data and
+
+429
+00:33:02,000 --> 00:33:03,000
+cluster.
+
+430
+00:33:06,000 --> 00:33:12,000
+According to naming convention, we use lowercase and the words are separated, which underscores their
+
+431
+00:33:12,000 --> 00:33:17,000
+tension that you have to specify maximum length of zero hour char.
+
+432
+00:33:17,000 --> 00:33:25,000
+By default, this forty five characters you can just click in data era type and change this limit.
+
+433
+00:33:26,000 --> 00:33:31,000
+And as I said, let me demo zero field property for our property.
+
+434
+00:33:31,000 --> 00:33:34,000
+We would adjust lengths of data time to five.
+
+435
+00:33:35,000 --> 00:33:38,000
+Also, we will select the checkbox.
+
+436
+00:33:38,000 --> 00:33:45,000
+So when you're ready, you can click Apply button sequel query will be shown for you to approve.
+
+437
+00:33:46,000 --> 00:33:48,000
+We're going to learn SQL in a separate lessons.
+
+438
+00:33:48,000 --> 00:33:54,000
+We'll also cover create table statements, but you already can start at least watching at these queries.
+
+439
+00:33:55,000 --> 00:33:56,000
+Click Apply Button.
+
+440
+00:33:57,000 --> 00:34:03,000
+Now, when our query is applied, we can find our table on the tables in our databases.
+
+441
+00:34:04,000 --> 00:34:07,000
+Let's expand that, and here's how I use our table.
+
+442
+00:34:07,000 --> 00:34:09,000
+Congratulations.
+
+443
+00:34:09,000 --> 00:34:11,000
+We have created our first table.
+
+444
+00:34:12,000 --> 00:34:19,000
+The looks are zeroes, mouse, right click select rows, and you can see separate up was sequel query
+
+445
+00:34:19,000 --> 00:34:22,000
+executed and representation of your table.
+
+446
+00:34:22,000 --> 00:34:25,000
+You can play with the stable by entering different values.
+
+447
+00:34:26,000 --> 00:34:27,000
+There are tensions.
+
+448
+00:34:27,000 --> 00:34:34,000
+Its values in email column should be unique, and you don't need to populate the column because it is
+
+449
+00:34:34,000 --> 00:34:35,000
+all the it.
+
+450
+00:34:42,000 --> 00:34:49,000
+Once you adjust that table, click Apply button again, you will see preview of insert statements,
+
+451
+00:34:49,000 --> 00:34:51,000
+click Apply one more time.
+
+452
+00:34:52,000 --> 00:34:58,000
+And now you can see that I.D. values have been generated and pay attention to the format.
+
+453
+00:34:58,000 --> 00:35:05,000
+The lengths of these five digits enumeration is going according to the regular number sequence, and
+
+454
+00:35:05,000 --> 00:35:07,000
+the rest digits are filled with zero.
+
+455
+00:35:08,000 --> 00:35:10,000
+That's what zero field property does.
+
+456
+00:35:11,000 --> 00:35:15,000
+But to be honest, I don't use this option very often.
+
+457
+00:35:15,000 --> 00:35:17,000
+But at least now you know what it does.
+
+458
+00:35:18,000 --> 00:35:19,000
+Wow.
+
+459
+00:35:19,000 --> 00:35:21,000
+We have learned a lot for the.
+
+460
+00:35:21,000 --> 00:35:24,000
+Let's recap what we have learned in this lesson.
+
+461
+00:35:25,000 --> 00:35:28,000
+In this lesson, we created our schema.
+
+462
+00:35:28,000 --> 00:35:33,000
+We learned what charset and collation is and which one I recommend to use.
+
+463
+00:35:34,000 --> 00:35:39,000
+You're in the lesson recovery topic of naming conventions for database objects.
+
+464
+00:35:39,000 --> 00:35:43,000
+Now, you know, recommended rules to follow during the naming of schemas.
+
+465
+00:35:43,000 --> 00:35:44,000
+Tables and columns.
+
+466
+00:35:45,000 --> 00:35:48,000
+After this lesson, you know what search engines are.
+
+467
+00:35:48,000 --> 00:35:54,000
+And you know, the difference between nine search engines in my school would have used different data
+
+468
+00:35:54,000 --> 00:35:55,000
+types in my school.
+
+469
+00:35:56,000 --> 00:36:02,000
+And at the end of the lesson, we learned column properties and create a table in database.
+
+470
+00:36:02,000 --> 00:36:04,000
+Thanks a lot for your attention.
+
+471
+00:36:04,000 --> 00:36:05,000
+Have a great day.
+
+472
+00:36:05,000 --> 00:36:07,000
+See you in the next lesson.
+

47 - Relational databases/003 Referential Integrity Foreign Key Constraint & Cascading Operations_en.srt

@@ -0,0 +1,1064 @@
+1
+00:00:05,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:12,000
+Today we're going to proceed our practical activities combined with some new piece of theory.
+
+3
+00:00:12,000 --> 00:00:18,000
+In this video, we proceed working with our first database tables that we created in the previous lesson.
+
+4
+00:00:19,000 --> 00:00:25,000
+We are going to learn more about referential integrity, foreign key constraints and cascading operations.
+
+5
+00:00:26,000 --> 00:00:32,000
+We'll start our lesson from understanding of referential integrity and potential consequences in case
+
+6
+00:00:32,000 --> 00:00:33,000
+it will be broken.
+
+7
+00:00:33,000 --> 00:00:39,000
+After that, we'll focus our attention on the solution for broken, referential integrity and how to
+
+8
+00:00:39,000 --> 00:00:41,000
+what is happening in your database.
+
+9
+00:00:42,000 --> 00:00:48,000
+We are going to review what cascading operations are and understand different types of cost-cutting
+
+10
+00:00:48,000 --> 00:00:49,000
+operations.
+
+11
+00:00:49,000 --> 00:00:56,000
+After that and practice, we are going to configure a foreign key constraint after review of all examples.
+
+12
+00:00:56,000 --> 00:01:02,000
+And by the end of this lesson, I am sure you will understand such concepts as data consistency, data
+
+13
+00:01:02,000 --> 00:01:05,000
+integrity, data quality and data validity.
+
+14
+00:01:06,000 --> 00:01:07,000
+Let's start the lesson.
+
+15
+00:01:08,000 --> 00:01:14,000
+And before we start altering our database table, let's try to understand problems that we are going
+
+16
+00:01:14,000 --> 00:01:15,000
+to avoid.
+
+17
+00:01:15,000 --> 00:01:18,000
+Let's talk about referential integrity.
+
+18
+00:01:19,000 --> 00:01:25,000
+Referential integrity is one of the most important and mandatory property in the relational database
+
+19
+00:01:25,000 --> 00:01:28,000
+that ensures that all references are valid.
+
+20
+00:01:29,000 --> 00:01:35,000
+So in case one attribute of a relational table reference is the value of another attribute, then the
+
+21
+00:01:35,000 --> 00:01:38,000
+reference value must exist.
+
+22
+00:01:39,000 --> 00:01:40,000
+In simple words.
+
+23
+00:01:40,000 --> 00:01:48,000
+Then it means that there are no references made by foreign keys to non-existent typos and to simplify
+
+24
+00:01:48,000 --> 00:01:49,000
+it even more.
+
+25
+00:01:49,000 --> 00:01:52,000
+It prohibits relations between tables using foreign keys.
+
+26
+00:01:53,000 --> 00:02:00,000
+We have to be sure that foreign key is referencing to valid and existing data because otherwise it is
+
+27
+00:02:00,000 --> 00:02:07,000
+not clear how to build relations between entities and case parent entity is not present in database
+
+28
+00:02:07,000 --> 00:02:08,000
+anymore.
+
+29
+00:02:09,000 --> 00:02:11,000
+Why referential integrity is important.
+
+30
+00:02:11,000 --> 00:02:16,000
+There are different issues that mafia during the corruption of referential integrity.
+
+31
+00:02:17,000 --> 00:02:23,000
+But the root cause of all issues is lost data because of corrupted integrity.
+
+32
+00:02:23,000 --> 00:02:31,000
+A lack of referential integrity in the database can lead to incomplete data being churned, sometimes
+
+33
+00:02:31,000 --> 00:02:33,000
+even with no indication of an error.
+
+34
+00:02:34,000 --> 00:02:41,000
+This could result in the records being lost in the database because there's never a chance inquiries
+
+35
+00:02:41,000 --> 00:02:44,000
+or reports, and the consequences might be different.
+
+36
+00:02:45,000 --> 00:02:50,000
+Your existing queries may not transcend specific fields from other tables.
+
+37
+00:02:50,000 --> 00:02:58,000
+Neurons across tune queries and this will produce some system error because the logic in court is usually
+
+38
+00:02:58,000 --> 00:03:04,000
+built in rounds of data to modify it and to process and use some data is absent.
+
+39
+00:03:05,000 --> 00:03:07,000
+Required logic is not triggered.
+
+40
+00:03:07,000 --> 00:03:16,000
+So I want you to understand that this is not just data consistency issue referential integrity potentially
+
+41
+00:03:16,000 --> 00:03:19,000
+may lead to not expected program behavior.
+
+42
+00:03:20,000 --> 00:03:25,000
+Let's review example of a problem, and let's try to find a solution for it.
+
+43
+00:03:25,000 --> 00:03:27,000
+Imagine that we have two tables.
+
+44
+00:03:28,000 --> 00:03:30,000
+They are user and roll.
+
+45
+00:03:31,000 --> 00:03:33,000
+Each user should have a role.
+
+46
+00:03:33,000 --> 00:03:38,000
+It can be user admin or content editor or employee or client.
+
+47
+00:03:39,000 --> 00:03:44,000
+There might be different roles here, but what is important?
+
+48
+00:03:44,000 --> 00:03:49,000
+There is one too many relationships between the role table and user table.
+
+49
+00:03:49,000 --> 00:03:55,000
+Each user may have only one role and each role may be assigned to multiple users.
+
+50
+00:03:56,000 --> 00:04:03,000
+And now imagine that we decided to remove content editor role and we decided to introduce different
+
+51
+00:04:03,000 --> 00:04:07,000
+roles in Step Media Editor and contributor.
+
+52
+00:04:08,000 --> 00:04:14,000
+Well, not that depends a business domain, because anyway, I want you to focus not on the specific
+
+53
+00:04:14,000 --> 00:04:22,000
+business issue, but on the technical one and step one of the role of TOPO is it contained information
+
+54
+00:04:22,000 --> 00:04:23,000
+about content editor.
+
+55
+00:04:23,000 --> 00:04:27,000
+What shall we do with foreign keys in our user table?
+
+56
+00:04:27,000 --> 00:04:31,000
+They still reference to the table that doesn't exist anymore.
+
+57
+00:04:32,000 --> 00:04:33,000
+Do understands the problem.
+
+58
+00:04:34,000 --> 00:04:41,000
+In case I would need to get full name for all users, what will I get for users that have known about
+
+59
+00:04:41,000 --> 00:04:42,000
+its reference?
+
+60
+00:04:42,000 --> 00:04:47,000
+This is exactly the problem that is caused by corruption of referential integrity.
+
+61
+00:04:48,000 --> 00:04:53,000
+How to prevent this happen, we need to set up foreign key constraint.
+
+62
+00:04:54,000 --> 00:04:56,000
+Let's understand now what it is.
+
+63
+00:04:57,000 --> 00:05:03,000
+The foreign key constraint is used to prevent actions that will destroy links between tables.
+
+64
+00:05:04,000 --> 00:05:11,000
+A foreign key is a field or collection of fields in one table that refers to the primary key in another
+
+65
+00:05:11,000 --> 00:05:12,000
+table.
+
+66
+00:05:12,000 --> 00:05:18,000
+The table with foreign key is called the child table, and the table was the primary.
+
+67
+00:05:18,000 --> 00:05:22,000
+Key is called the reference or parent table.
+
+68
+00:05:22,000 --> 00:05:29,000
+In our particular example, user table contains column was named after a user role.
+
+69
+00:05:29,000 --> 00:05:36,000
+This is exactly foreign key that allows us to build relationships between user and role tables.
+
+70
+00:05:37,000 --> 00:05:43,000
+Now, let's think how we can figure that issue was foreign key constraint and how exactly it will prevent
+
+71
+00:05:43,000 --> 00:05:45,000
+corruption of referential integrity.
+
+72
+00:05:46,000 --> 00:05:51,000
+Let me suggest a few ideas how to avoid corruption of referential integrity.
+
+73
+00:05:51,000 --> 00:05:59,000
+The first option is just to forbid removal and the date of Toptal in case some other tables contains
+
+74
+00:05:59,000 --> 00:06:00,000
+a reference to it.
+
+75
+00:06:00,000 --> 00:06:08,000
+In this case, we can't remove content editor role or update its I-D until some references exist.
+
+76
+00:06:09,000 --> 00:06:12,000
+The second option is to remove all related records.
+
+77
+00:06:12,000 --> 00:06:19,000
+For example, if I remove content editor role, then keeping content editor users in the system makes
+
+78
+00:06:19,000 --> 00:06:22,000
+no sense, and I also remove related users.
+
+79
+00:06:23,000 --> 00:06:31,000
+Now, imagine that instead of removing Content Editor, you just decided to update it and you change
+
+80
+00:06:31,000 --> 00:06:33,000
+the primary key and the role name.
+
+81
+00:06:33,000 --> 00:06:37,000
+In this case, we update all references was updated primary key.
+
+82
+00:06:38,000 --> 00:06:42,000
+Another option is to set null values instead of all references.
+
+83
+00:06:43,000 --> 00:06:50,000
+You may also consider this option, but again, in this case, you have to have logical place that process
+
+84
+00:06:50,000 --> 00:06:54,000
+null values that you would receive in response instead of required data.
+
+85
+00:06:55,000 --> 00:07:02,000
+And all value is a special marker used in school to indicate that a data value doesn't exist in the
+
+86
+00:07:02,000 --> 00:07:03,000
+database.
+
+87
+00:07:04,000 --> 00:07:11,000
+In other words, it is just a placeholder to denote values that missing was that we don't know.
+
+88
+00:07:12,000 --> 00:07:19,000
+And last but not least, is setting default value instead of all references, for example, in this
+
+89
+00:07:19,000 --> 00:07:22,000
+case, one content editor role has been removed.
+
+90
+00:07:23,000 --> 00:07:26,000
+We can set default reference to employee role records.
+
+91
+00:07:27,000 --> 00:07:34,000
+That means that all references to Content Editor role will be substituted with references to employee
+
+92
+00:07:34,000 --> 00:07:34,000
+role.
+
+93
+00:07:36,000 --> 00:07:39,000
+All these options are called cascading operations.
+
+94
+00:07:40,000 --> 00:07:47,000
+These operations are special kind of database restrictions that describe his behavior in case of removal
+
+95
+00:07:47,000 --> 00:07:53,000
+record from parent table or in case updating of its primary key.
+
+96
+00:07:53,000 --> 00:07:54,000
+Does it make sense?
+
+97
+00:07:55,000 --> 00:08:02,000
+And then the lesson we are going to learn how to set up these restrictions in our table on practice.
+
+98
+00:08:03,000 --> 00:08:10,000
+So to sum it up, we can configure foreign key constraint on update or on the lead off primary key in
+
+99
+00:08:10,000 --> 00:08:11,000
+parent table.
+
+100
+00:08:12,000 --> 00:08:17,000
+Foreign key constraint may be of the following types restrict.
+
+101
+00:08:17,000 --> 00:08:25,000
+This restricts any cost current operations, so we have to make sure first that we removed all references
+
+102
+00:08:25,000 --> 00:08:33,000
+to this table and only after that remove or update the primary key in parent table cascade.
+
+103
+00:08:34,000 --> 00:08:41,000
+This option will update foreign key in child tables in case it was updated and will remove double from
+
+104
+00:08:41,000 --> 00:08:46,000
+child table in case primary key and parent table has been removed.
+
+105
+00:08:46,000 --> 00:08:53,000
+Set now based on the name, you can make an assumption what does assumption that it sets?
+
+106
+00:08:53,000 --> 00:08:58,000
+Now, instead of foreign key, it's the last one was either updated or removed.
+
+107
+00:08:59,000 --> 00:09:00,000
+No action.
+
+108
+00:09:01,000 --> 00:09:03,000
+Is this a so-so options of disposable tissues?
+
+109
+00:09:03,000 --> 00:09:10,000
+But I'm not sure whether you will need it, because the whole idea of foreign key constraint is to set
+
+110
+00:09:10,000 --> 00:09:16,000
+up a constraint, but not just select no action option and ignore things, said default.
+
+111
+00:09:17,000 --> 00:09:21,000
+You can substitute reference to the foreign key was the default value.
+
+112
+00:09:22,000 --> 00:09:28,000
+While this is also one of the foreign key constraints, you won't be able to find this option in my
+
+113
+00:09:28,000 --> 00:09:29,000
+school workbench.
+
+114
+00:09:30,000 --> 00:09:37,000
+Also, you wouldn't be able to set said default option or be a sequel query because it is simply not
+
+115
+00:09:37,000 --> 00:09:41,000
+supported by inadequate storage engine in my school.
+
+116
+00:09:41,000 --> 00:09:47,000
+Still, there is a workaround was usage of triggers in my school, but we haven't learned how to work
+
+117
+00:09:47,000 --> 00:09:49,000
+with triggers in a separate lesson.
+
+118
+00:09:50,000 --> 00:09:53,000
+And now there's exactly time for the live demo.
+
+119
+00:09:53,000 --> 00:09:56,000
+Let's learn in practice how to set foreign key constraint.
+
+120
+00:09:58,000 --> 00:10:05,000
+Bruce Larson, we created with you user table in case you didn't watch that lesson and don't know how
+
+121
+00:10:05,000 --> 00:10:06,000
+to create tables.
+
+122
+00:10:06,000 --> 00:10:09,000
+Please watch it if you have a user table.
+
+123
+00:10:10,000 --> 00:10:13,000
+We are going to proceed for the sake of the demo.
+
+124
+00:10:13,000 --> 00:10:15,000
+We need one more table.
+
+125
+00:10:15,000 --> 00:10:17,000
+Let's create role table now.
+
+126
+00:10:18,000 --> 00:10:23,000
+I already created this table before the lesson to save the time during the video lesson.
+
+127
+00:10:24,000 --> 00:10:30,000
+If you need time to create a table grasp, pause for a minute and then resume VIDEO when you are ready.
+
+128
+00:10:31,000 --> 00:10:33,000
+This table has only two fields.
+
+129
+00:10:33,000 --> 00:10:36,000
+They are ID and role name.
+
+130
+00:10:36,000 --> 00:10:37,000
+That's it.
+
+131
+00:10:38,000 --> 00:10:42,000
+When you created this table, please calculated, was valleys.
+
+132
+00:10:42,000 --> 00:10:45,000
+It is not critically important what would be a role name?
+
+133
+00:10:46,000 --> 00:10:50,000
+The main thing here is to have at least a few roles for demo purposes.
+
+134
+00:10:51,000 --> 00:10:57,000
+If you wish, you can create the values as I have, and when you add its values into the role table,
+
+135
+00:10:58,000 --> 00:10:59,000
+we are done with it.
+
+136
+00:10:59,000 --> 00:11:05,000
+And again, if you don't know how to add value in table, we are my school workbench.
+
+137
+00:11:06,000 --> 00:11:08,000
+Please refer to the previous lesson.
+
+138
+00:11:09,000 --> 00:11:13,000
+Now we need to establish relationships between the role and user tables.
+
+139
+00:11:14,000 --> 00:11:20,000
+If you remember lesson about relational database basic concepts, then you should remember that one
+
+140
+00:11:20,000 --> 00:11:25,000
+too many relationships is implemented by adding foreign key into another table.
+
+141
+00:11:26,000 --> 00:11:28,000
+We need to adjust our user table now.
+
+142
+00:11:29,000 --> 00:11:35,000
+I do mouse right click on the user table and I select Alter Table Option.
+
+143
+00:11:35,000 --> 00:11:40,000
+In this view, we need to add one more column for foreign key.
+
+144
+00:11:40,000 --> 00:11:47,000
+There is an agreed naming convention for the name of the foreign key, while you still can name it as
+
+145
+00:11:47,000 --> 00:11:48,000
+you want.
+
+146
+00:11:48,000 --> 00:11:57,000
+I would recommend you two fellows and next partner f k that stands for foreign key, followed by Underscore,
+
+147
+00:11:58,000 --> 00:12:00,000
+followed by foreign key table name.
+
+148
+00:12:00,000 --> 00:12:06,000
+In our case for table name is a target table xCurrent one.
+
+149
+00:12:06,000 --> 00:12:14,000
+Thus, I like to use R after f k after that again goes underscore, and this time it is followed by
+
+150
+00:12:14,000 --> 00:12:16,000
+primary key table.
+
+151
+00:12:16,000 --> 00:12:20,000
+This is our source table in this particular case.
+
+152
+00:12:20,000 --> 00:12:22,000
+This is roll table.
+
+153
+00:12:23,000 --> 00:12:28,000
+This is why we have such name for a foreign key column f k user role.
+
+154
+00:12:29,000 --> 00:12:36,000
+Considering that we use surrogate primary key in the role table, we have to use each type for the foreign
+
+155
+00:12:36,000 --> 00:12:37,000
+key column to.
+
+156
+00:12:39,000 --> 00:12:44,000
+When we are done with creation of the calling for the foreign key, let's open another tap.
+
+157
+00:12:44,000 --> 00:12:46,000
+I open foreign key staff.
+
+158
+00:12:47,000 --> 00:12:52,000
+This is exactly the type where we can configure foreign key constraint on the database level.
+
+159
+00:12:53,000 --> 00:12:55,000
+Specify foreign key name.
+
+160
+00:12:55,000 --> 00:13:00,000
+This is just a name for foreign key constraint in reference tables.
+
+161
+00:13:00,000 --> 00:13:03,000
+Select the parent table the tables.
+
+162
+00:13:03,000 --> 00:13:10,000
+It contains primary keys that we are referencing to, and after that you have opportunity to select.
+
+163
+00:13:10,000 --> 00:13:16,000
+The column was foreign key in the current table and specify reference column in the parent table.
+
+164
+00:13:17,000 --> 00:13:20,000
+Now why do we consider that connection?
+
+165
+00:13:20,000 --> 00:13:23,000
+Let me specify foreign key options here.
+
+166
+00:13:23,000 --> 00:13:30,000
+Usually, you can specify constraints on update and on delete operations in parenting mode for the sake
+
+167
+00:13:30,000 --> 00:13:31,000
+of the demo.
+
+168
+00:13:31,000 --> 00:13:34,000
+Let me set restrict options here.
+
+169
+00:13:34,000 --> 00:13:36,000
+I click apply by them.
+
+170
+00:13:36,000 --> 00:13:40,000
+You also can check SQL queries it is going to be executed.
+
+171
+00:13:41,000 --> 00:13:44,000
+Don't worry, one will come to learn in the sequel.
+
+172
+00:13:44,000 --> 00:13:47,000
+We are going to also cover alter table queries.
+
+173
+00:13:47,000 --> 00:13:51,000
+But still, it is good for you to be at least familiar with squares.
+
+174
+00:13:52,000 --> 00:13:59,000
+My concept of the Asian database is to let you understand operations that we need to execute against
+
+175
+00:13:59,000 --> 00:14:02,000
+database and when we need to execute them.
+
+176
+00:14:02,000 --> 00:14:11,000
+This gives my students understanding of end to end flow, and one will understand this will go to details
+
+177
+00:14:11,000 --> 00:14:13,000
+and will learn SQL itself.
+
+178
+00:14:13,000 --> 00:14:18,000
+I hope this approach will also help you to learn the topic faster.
+
+179
+00:14:19,000 --> 00:14:27,000
+In our user, a table, we have new fields now, let's put foreign keys for each user just to help you
+
+180
+00:14:27,000 --> 00:14:34,000
+understand I I.D. of Topo from rolls table to establish one to many relationships.
+
+181
+00:14:35,000 --> 00:14:39,000
+It isn't critically important in which one role will be assigned to each user.
+
+182
+00:14:40,000 --> 00:14:45,000
+Since this is all fake data, that's why I put these in random order.
+
+183
+00:14:45,000 --> 00:14:50,000
+Here is the interest in seeing the demo in roundtable.
+
+184
+00:14:50,000 --> 00:14:56,000
+We have maximum and equal to six basically Z values from one to six.
+
+185
+00:14:57,000 --> 00:15:05,000
+What will happen if I would try to set, for example, value 10 in foreign key column, I put Dan and
+
+186
+00:15:06,000 --> 00:15:07,000
+click Apply.
+
+187
+00:15:08,000 --> 00:15:13,000
+You can see that the reason there because was set, that'd be something like this.
+
+188
+00:15:13,000 --> 00:15:18,000
+This database, I want to establish relationships between two tables.
+
+189
+00:15:18,000 --> 00:15:23,000
+And this column will be used as foreign key to reference the parent table primary key.
+
+190
+00:15:24,000 --> 00:15:29,000
+And our database listen to us and do what we asked it to do.
+
+191
+00:15:29,000 --> 00:15:36,000
+That's why you can't add reference to non-existent primary key and parent table.
+
+192
+00:15:37,000 --> 00:15:38,000
+Let me open the roll table.
+
+193
+00:15:39,000 --> 00:15:45,000
+In case I'd like to remove all the participating relationships was record from another table.
+
+194
+00:15:45,000 --> 00:15:47,000
+I wouldn't be able to do that.
+
+195
+00:15:48,000 --> 00:15:51,000
+I can't do miles right click on the road and select the lead role.
+
+196
+00:15:52,000 --> 00:16:00,000
+After that, I click Apply button that the base doesn't let me remove zero because we restrict its removal
+
+197
+00:16:00,000 --> 00:16:04,000
+in this case, if you want to remove Roe was a new one.
+
+198
+00:16:04,000 --> 00:16:11,000
+We have to remove all references to this record in other tables, and only after that we will be able
+
+199
+00:16:11,000 --> 00:16:14,000
+to remove this rule does it make sense.
+
+200
+00:16:15,000 --> 00:16:19,000
+So our SQL query wasn't executed successfully.
+
+201
+00:16:19,000 --> 00:16:22,000
+That's why I click on Execute Query.
+
+202
+00:16:22,000 --> 00:16:27,000
+I can hear one more time, and here's our row back again.
+
+203
+00:16:28,000 --> 00:16:35,000
+It is still stored in Libby and is always guys not shy to ask questions and comments on this, we knew
+
+204
+00:16:35,000 --> 00:16:36,000
+in case you have any.
+
+205
+00:16:37,000 --> 00:16:39,000
+I always will be happy to answer.
+
+206
+00:16:40,000 --> 00:16:47,000
+Now, let's demo another thing I need to all to use a table one more time to demo you and not just sing.
+
+207
+00:16:48,000 --> 00:16:55,000
+Now, in certain key options, I'm going to select Cascade, what we expect now on that date.
+
+208
+00:16:55,000 --> 00:16:58,000
+Foreign key should be updated on remove.
+
+209
+00:16:58,000 --> 00:17:00,000
+Related records will be removed.
+
+210
+00:17:01,000 --> 00:17:06,000
+Let's get back to the table in his updated primary key for one record.
+
+211
+00:17:07,000 --> 00:17:09,000
+It will be updated in another table.
+
+212
+00:17:13,000 --> 00:17:15,000
+Let me open user table now.
+
+213
+00:17:16,000 --> 00:17:21,000
+You also can see that foreign key has been changed once I refreshed table.
+
+214
+00:17:22,000 --> 00:17:28,000
+So refresh table, you need to execute select queries, it was prepared by my school workbench one more
+
+215
+00:17:28,000 --> 00:17:28,000
+time.
+
+216
+00:17:29,000 --> 00:17:34,000
+Let me open the roll table again and let me remove zero plays its role.
+
+217
+00:17:35,000 --> 00:17:39,000
+I execute this query, no error so far.
+
+218
+00:17:39,000 --> 00:17:46,000
+And once this query is executed and Temple is removed from parent table with triggered cascading operation
+
+219
+00:17:46,000 --> 00:17:49,000
+in a related table on the delete event.
+
+220
+00:17:49,000 --> 00:17:53,000
+All related rows should be also removed in cascade cascading manner.
+
+221
+00:17:54,000 --> 00:17:59,000
+Let me refresh your user table and you can see that throws the reference to the tackles that we have
+
+222
+00:17:59,000 --> 00:18:01,000
+just removed is also removed.
+
+223
+00:18:02,000 --> 00:18:04,000
+Let's adjust foreign key constraint.
+
+224
+00:18:04,000 --> 00:18:07,000
+And this time we'll select said no.
+
+225
+00:18:13,000 --> 00:18:15,000
+Once we apply, it all changes.
+
+226
+00:18:15,000 --> 00:18:22,000
+I assume you can understand what will happen in case a remove role in parent table or update primer
+
+227
+00:18:22,000 --> 00:18:26,000
+key Zen related values in foreign key will be set up.
+
+228
+00:18:27,000 --> 00:18:33,000
+That's all possible because current operations is that you can perform in my school in tables was not
+
+229
+00:18:33,000 --> 00:18:34,000
+in the engine.
+
+230
+00:18:34,000 --> 00:18:35,000
+I don't know them.
+
+231
+00:18:35,000 --> 00:18:38,000
+You last for restrictions at the schools.
+
+232
+00:18:38,000 --> 00:18:43,000
+No action because I assume you are smart enough to understand what will happen.
+
+233
+00:18:44,000 --> 00:18:50,000
+And if you want to remove foreign key constraint, just open table configurations by selecting all the
+
+234
+00:18:50,000 --> 00:18:57,000
+table one more time and click the lead, select it on the foreign key constraint and take the kids query.
+
+235
+00:18:57,000 --> 00:18:58,000
+That's it.
+
+236
+00:18:59,000 --> 00:19:05,000
+On this example, I believe you already understood what data, consistency and data validity means.
+
+237
+00:19:06,000 --> 00:19:11,000
+In other words, this is nothing more than referential integrity and internal consistency.
+
+238
+00:19:12,000 --> 00:19:19,000
+Data consistency means that there is consistency in measurement of variables throughout data sets.
+
+239
+00:19:20,000 --> 00:19:28,000
+Data integrity is the overall accuracy and consistency of data and database can be set to be data consistent.
+
+240
+00:19:28,000 --> 00:19:36,000
+Once the content and the question doesn't give us a chance to infer a contradiction directly or indirectly,
+
+241
+00:19:37,000 --> 00:19:41,000
+data can be entirely consistent, but entirely wrong.
+
+242
+00:19:41,000 --> 00:19:46,000
+So the phrase data integrity is about the quality of data.
+
+243
+00:19:46,000 --> 00:19:53,000
+Database management systems provide data consistency tools, which can help around data integrity.
+
+244
+00:19:54,000 --> 00:20:00,000
+These are the parameters which are used to indicate the condition of data, such as data quality.
+
+245
+00:20:01,000 --> 00:20:04,000
+Data quality is a measurement of the condition of data.
+
+246
+00:20:04,000 --> 00:20:12,000
+Considering factors such as accuracy, completeness, consistency, data integrity is not about data
+
+247
+00:20:12,000 --> 00:20:13,000
+quality.
+
+248
+00:20:13,000 --> 00:20:20,000
+Data quality answer some questions, such as meetings or defined standards of an organization.
+
+249
+00:20:20,000 --> 00:20:23,000
+Data quality is a part of data integrity.
+
+250
+00:20:24,000 --> 00:20:32,000
+Data integrity includes all aspects of data quality and also force rules and includes review one more
+
+251
+00:20:32,000 --> 00:20:34,000
+term like data validity.
+
+252
+00:20:35,000 --> 00:20:41,000
+It is worth to say that this is just an aspect of data quality consistent in its settings.
+
+253
+00:20:41,000 --> 00:20:46,000
+This is a natural process of data obsolescence increase in time.
+
+254
+00:20:47,000 --> 00:20:48,000
+Stay tuned.
+
+255
+00:20:48,000 --> 00:20:54,000
+We'll have a lot of lessons where we'll discuss tools and techniques to ensure the best data quality.
+
+256
+00:20:54,000 --> 00:20:56,000
+That's all for this lesson.
+
+257
+00:20:56,000 --> 00:21:03,000
+Let's recap what we have learned today in this lesson, we have learned what referential integrity is
+
+258
+00:21:03,000 --> 00:21:04,000
+now.
+
+259
+00:21:04,000 --> 00:21:07,000
+You know what consequences of broken, referential integrity are.
+
+260
+00:21:08,000 --> 00:21:13,000
+We learned the concept of cascading operations and practice activities.
+
+261
+00:21:13,000 --> 00:21:16,000
+We can figure foreign key constraint in our tables.
+
+262
+00:21:16,000 --> 00:21:22,000
+I am sure that after this lesson, you have a clear understanding of what data consistency, data integrity,
+
+263
+00:21:23,000 --> 00:21:25,000
+data quality and data related to is.
+
+264
+00:21:26,000 --> 00:21:27,000
+Thanks a lot for your attention.
+
+265
+00:21:28,000 --> 00:21:29,000
+Have a great day.
+
+266
+00:21:29,000 --> 00:21:31,000
+See you in the next lesson.
+

47 - Relational databases/004 Indexes in Databases_en.srt

@@ -0,0 +1,988 @@
+1
+00:00:05,000 --> 00:00:06,000
+Hello.
+
+2
+00:00:06,000 --> 00:00:10,000
+Yes, tenants in this lesson, we're going to learn indexes and databases.
+
+3
+00:00:10,000 --> 00:00:13,000
+I will explain you what they are and why we need them.
+
+4
+00:00:14,000 --> 00:00:16,000
+Also, we'll have practiced during the lesson.
+
+5
+00:00:16,000 --> 00:00:22,000
+We'll create a few indexes for our existing tables that we created in previous videos.
+
+6
+00:00:23,000 --> 00:00:28,000
+In the lesson, we're going to learn definition of index, and I will explain you what it is.
+
+7
+00:00:28,000 --> 00:00:32,000
+One example you're going to understand why we need indexes.
+
+8
+00:00:33,000 --> 00:00:40,000
+Also, we're going to give you a different index types Ziya primary, secondary and clustering.
+
+9
+00:00:41,000 --> 00:00:45,000
+Also, we're going to have a practice during the lesson in my school workbench.
+
+10
+00:00:45,000 --> 00:00:51,000
+We're going to learn how to create indexes kind of figures, work with different properties and delays.
+
+11
+00:00:52,000 --> 00:00:58,000
+And as a summary, at the end of the lesson, we're going to review advantages and disadvantages of
+
+12
+00:00:58,000 --> 00:00:59,000
+using indexes.
+
+13
+00:01:00,000 --> 00:01:01,000
+Let's start our lesson.
+
+14
+00:01:02,000 --> 00:01:10,000
+We're going to start our lesson with definition of indexes, so what indexes indexes, the data structures,
+
+15
+00:01:10,000 --> 00:01:17,000
+it improves the speed of data retrieval operations on a database table and the cost of additional rights
+
+16
+00:01:17,000 --> 00:01:18,000
+and storage space.
+
+17
+00:01:19,000 --> 00:01:21,000
+The main things are index data structure.
+
+18
+00:01:22,000 --> 00:01:28,000
+Indexes are used to quickly allocate data without having to search every row in a database table.
+
+19
+00:01:28,000 --> 00:01:31,000
+Every time and database table is accessed.
+
+20
+00:01:32,000 --> 00:01:40,000
+Indexes can be created using one or more columns of a database table provides a basis for both rapid
+
+21
+00:01:40,000 --> 00:01:47,000
+random lookups, and the efficient access of order records in the minutes will explain what lookups
+
+22
+00:01:47,000 --> 00:01:49,000
+are then distant.
+
+23
+00:01:49,000 --> 00:01:50,000
+What is an index?
+
+24
+00:01:51,000 --> 00:01:56,000
+In most simple words, and index is a small table having only two columns.
+
+25
+00:01:56,000 --> 00:02:00,000
+The first column is a copy of the primary key off a table.
+
+26
+00:02:00,000 --> 00:02:08,000
+The second column contains a set of pointers for holding the address of the disk block, whereas it's
+
+27
+00:02:08,000 --> 00:02:10,000
+specific related to accurate is stored.
+
+28
+00:02:11,000 --> 00:02:14,000
+In some cases, index is sorted and extracted.
+
+29
+00:02:14,000 --> 00:02:18,000
+The reference to the records become easier thing to do.
+
+30
+00:02:18,000 --> 00:02:23,000
+An operation is significantly faster rather than going over each row.
+
+31
+00:02:24,000 --> 00:02:28,000
+Before we move further was none of indexes in details.
+
+32
+00:02:28,000 --> 00:02:34,000
+I promised you to explain what lookup tables are in computer science.
+
+33
+00:02:34,000 --> 00:02:41,000
+A lookup table isn't the rate that replaces runtime computation with a simpler rate indexing operation.
+
+34
+00:02:42,000 --> 00:02:49,000
+The savings in processing time can be significant because retrieving a value from memory is often faster
+
+35
+00:02:49,000 --> 00:02:54,000
+than carrying out an expensive computation or input output operation.
+
+36
+00:02:55,000 --> 00:02:59,000
+The tables may be calculated and stored in static storage.
+
+37
+00:03:00,000 --> 00:03:06,000
+This assumption doesn't require for a separate lesson, but still important for you to know this chunk.
+
+38
+00:03:07,000 --> 00:03:14,000
+Sometimes you're going to create such lookup tables or just how easy called lookups in your database
+
+39
+00:03:15,000 --> 00:03:21,000
+and definitely indexing will help you significantly improve performance of your app by reducing the
+
+40
+00:03:21,000 --> 00:03:24,000
+time of computation to find the value you need.
+
+41
+00:03:25,000 --> 00:03:30,000
+That was a small step aside to make sure you understood all terms I mentioned.
+
+42
+00:03:31,000 --> 00:03:36,000
+Let's understand now in more detail what does indexing do and why?
+
+43
+00:03:36,000 --> 00:03:39,000
+It is important and deserves a separate lesson.
+
+44
+00:03:40,000 --> 00:03:47,000
+Indexing is a way to get an order table into an order that will maximize the query efficiency.
+
+45
+00:03:47,000 --> 00:03:55,000
+While searching one table is an index is the order of the rows will likely not to be discernable by
+
+46
+00:03:55,000 --> 00:04:03,000
+the query as optimized in any way, and your query will therefore have to search through the rows leniently.
+
+47
+00:04:03,000 --> 00:04:10,000
+In other words, the queries will have to search through every rule to find zeros matching the conditions.
+
+48
+00:04:11,000 --> 00:04:14,000
+As you can imagine, this can take a long time.
+
+49
+00:04:14,000 --> 00:04:18,000
+Looking through every single row is not very efficient.
+
+50
+00:04:18,000 --> 00:04:26,000
+Imagine that you have a list of users in your database and that 100000 of them and you need to find
+
+51
+00:04:26,000 --> 00:04:27,000
+the user by its email.
+
+52
+00:04:28,000 --> 00:04:34,000
+You can pass users email as a search query to a database, but to find zeros.
+
+53
+00:04:34,000 --> 00:04:36,000
+It's a unique database will go over each row.
+
+54
+00:04:36,000 --> 00:04:41,000
+Compare and email in a search query was the actual email in each table.
+
+55
+00:04:42,000 --> 00:04:45,000
+How much time will it take to iterate over each couple?
+
+56
+00:04:46,000 --> 00:04:46,000
+Would this soon?
+
+57
+00:04:47,000 --> 00:04:55,000
+Well, believe me, it will take time in the sense of post to improve the performance of the database
+
+58
+00:04:55,000 --> 00:05:00,000
+while reading data from an index causes the database to create a data structure.
+
+59
+00:05:01,000 --> 00:05:07,000
+In this data structure, with a search term and pointer to the actual records in the database, for
+
+60
+00:05:07,000 --> 00:05:11,000
+example, index can be created for email column.
+
+61
+00:05:11,000 --> 00:05:16,000
+In this case, index will consist from the email value and point that does.
+
+62
+00:05:16,000 --> 00:05:22,000
+A table associated with this email pointer is, simply speaking, the reference information for the
+
+63
+00:05:22,000 --> 00:05:26,000
+location of the additional information in memory.
+
+64
+00:05:26,000 --> 00:05:33,000
+Basically, the index holds is a search term and that particular rows home address on the memory disk
+
+65
+00:05:34,000 --> 00:05:41,000
+index records comprise such key values and data pointers, multilevel indexes, stores and the disk,
+
+66
+00:05:41,000 --> 00:05:43,000
+along with the actual database files.
+
+67
+00:05:44,000 --> 00:05:48,000
+As the size of the database grows, so does the size of the indexes.
+
+68
+00:05:49,000 --> 00:05:56,000
+There is an immense need to keep the index records in the main memory so as to speed up the search operations.
+
+69
+00:05:56,000 --> 00:06:03,000
+If single level indexes used in the large size index can not be kept in memory, which leads to multiple
+
+70
+00:06:03,000 --> 00:06:11,000
+disk accesses, Multilevel Index helps in breaking down the index into several smaller indexes in order
+
+71
+00:06:11,000 --> 00:06:18,000
+to make the outermost level so small that it can be saved in a single disk block, which can easily
+
+72
+00:06:18,000 --> 00:06:21,000
+be accommodated anywhere in the main memory.
+
+73
+00:06:22,000 --> 00:06:25,000
+The index data structure tarp is very likely and B three.
+
+74
+00:06:26,000 --> 00:06:26,000
+What is it?
+
+75
+00:06:27,000 --> 00:06:32,000
+In case you are not familiar with this kind of the destruction, I will briefly explain the main points
+
+76
+00:06:32,000 --> 00:06:32,000
+now.
+
+77
+00:06:33,000 --> 00:06:35,000
+Well, the advantage of the big three are numerous.
+
+78
+00:06:36,000 --> 00:06:42,000
+The main advantage for our purposes is that it is searchable when the data structure is sorted in order.
+
+79
+00:06:42,000 --> 00:06:45,000
+It makes our search more efficient for obvious reasons.
+
+80
+00:06:46,000 --> 00:06:53,000
+So the definition of victory sounds like this mitre is a self-balancing tree data structure that maintains
+
+81
+00:06:53,000 --> 00:06:55,000
+source data and allows searches.
+
+82
+00:06:56,000 --> 00:07:04,000
+Sequential access insertions and deletions in logarithmic time and arbitrary is a balanced binary search
+
+83
+00:07:04,000 --> 00:07:07,000
+tree that follows a multilevel index format.
+
+84
+00:07:07,000 --> 00:07:11,000
+The leaf nodes of a tree denote actual data point.
+
+85
+00:07:11,000 --> 00:07:17,000
+This V3 ensures that all leaf must remain as the same height.
+
+86
+00:07:17,000 --> 00:07:18,000
+Thus, balance.
+
+87
+00:07:19,000 --> 00:07:23,000
+Additionally, the leaf nodes are linked using Eliquis.
+
+88
+00:07:24,000 --> 00:07:29,000
+Therefore, Arbitrary can support random access as well as sequential access.
+
+89
+00:07:30,000 --> 00:07:35,000
+If you want to run this data structure in details, I have a course where I reviewed different data
+
+90
+00:07:35,000 --> 00:07:38,000
+structures on examples of containers in Java.
+
+91
+00:07:39,000 --> 00:07:40,000
+But the general idea is the same.
+
+92
+00:07:41,000 --> 00:07:44,000
+You can check my Java Collections framework course if you wish.
+
+93
+00:07:45,000 --> 00:07:49,000
+I also explained in details would be connotation is in that course.
+
+94
+00:07:50,000 --> 00:07:53,000
+Now let's proceed with learning of indexes.
+
+95
+00:07:54,000 --> 00:07:58,000
+I'm going to explain in now different types of indexes the three types of Zen.
+
+96
+00:07:59,000 --> 00:08:07,000
+They are primary secondary clustering, primary index and turn maybe dance or sparse.
+
+97
+00:08:07,000 --> 00:08:14,000
+Primary index refers to an index stored in sorted order on the certain key of data storage and blocks
+
+98
+00:08:15,000 --> 00:08:16,000
+to look up a value.
+
+99
+00:08:17,000 --> 00:08:23,000
+You do a binary search on the index, which will produce a pointer to the blog, and then you can do
+
+100
+00:08:23,000 --> 00:08:26,000
+a binary search on the data in the block.
+
+101
+00:08:26,000 --> 00:08:28,000
+Let's start from the primary index.
+
+102
+00:08:29,000 --> 00:08:35,000
+Primary indexes and orders file, which is fixed length size, which still feels and like we have previously
+
+103
+00:08:35,000 --> 00:08:36,000
+discussed.
+
+104
+00:08:36,000 --> 00:08:43,000
+The first field is the same as index value, and second is a pointer to that specific data block.
+
+105
+00:08:43,000 --> 00:08:50,000
+We can say that there is always one to one relationship between the entries in the index table you already
+
+106
+00:08:50,000 --> 00:08:52,000
+know from previous slide.
+
+107
+00:08:52,000 --> 00:09:00,000
+The primary index member is a dense or sparse and dense indexing database is an index was pairs of keys
+
+108
+00:09:00,000 --> 00:09:02,000
+and pointers for every records.
+
+109
+00:09:02,000 --> 00:09:08,000
+Every key in this file is associated with a particular point that the record in the source of data file.
+
+110
+00:09:09,000 --> 00:09:15,000
+This means that the number of records in the index table is the same as the number of records in the
+
+111
+00:09:15,000 --> 00:09:16,000
+main table.
+
+112
+00:09:17,000 --> 00:09:24,000
+Obviously, this type of index needs more space to store index records itself in comparison with sparse
+
+113
+00:09:24,000 --> 00:09:25,000
+primary index.
+
+114
+00:09:26,000 --> 00:09:29,000
+The Spurs primary index is somewhat different.
+
+115
+00:09:29,000 --> 00:09:34,000
+It is an index record that appears for only some of the values in the file.
+
+116
+00:09:35,000 --> 00:09:41,000
+Sparse Index helps you to resolve the issues of dense index and database management system.
+
+117
+00:09:42,000 --> 00:09:49,000
+Following this indexing technique, a range of index columns stores the same data block address, and
+
+118
+00:09:49,000 --> 00:09:53,000
+when data needs to be retrieved, the block address will be fetched.
+
+119
+00:09:54,000 --> 00:09:57,000
+This is key difference between dance and sports in this.
+
+120
+00:09:58,000 --> 00:10:03,000
+Let me repeat one more time, in other words, and pay attention to the visualisation of the slide.
+
+121
+00:10:03,000 --> 00:10:07,000
+To understand this better, we have blocks that source.
+
+122
+00:10:07,000 --> 00:10:15,000
+A range of data is a clear and based on the search query, I get access to the block of data.
+
+123
+00:10:16,000 --> 00:10:20,000
+After that, we'll go over the data and look linearly till we get the requested data.
+
+124
+00:10:21,000 --> 00:10:28,000
+Also, in comparison to dancing, surpassing the source index records for only some search key values.
+
+125
+00:10:28,000 --> 00:10:35,000
+Thus, its advantage in requiring less space, less maintenance overhead for insertion and deletions.
+
+126
+00:10:36,000 --> 00:10:40,000
+So as you already understood, sparse index is called.
+
+127
+00:10:40,000 --> 00:10:47,000
+So because we need less number of pointers from index, the records of database all records are arranged
+
+128
+00:10:47,000 --> 00:10:55,000
+based on order is key, and hence we can quickly access the record by going to block first and then
+
+129
+00:10:55,000 --> 00:11:00,000
+access the following records without having individual index for each of the records.
+
+130
+00:11:00,000 --> 00:11:01,000
+Does it make sense?
+
+131
+00:11:02,000 --> 00:11:08,000
+We are done with primary in this, even in case you have any questions related to primary index.
+
+132
+00:11:08,000 --> 00:11:15,000
+Please do not hesitate to ask your questions in the comments to this video, and I will be happy to
+
+133
+00:11:15,000 --> 00:11:15,000
+answer.
+
+134
+00:11:16,000 --> 00:11:18,000
+Let's move on now.
+
+135
+00:11:18,000 --> 00:11:20,000
+Let's discuss and learn what secondary indexes.
+
+136
+00:11:21,000 --> 00:11:28,000
+In the index in database management system can be generated by a field which has a unique value for
+
+137
+00:11:28,000 --> 00:11:31,000
+each record, and it should be a candidate key.
+
+138
+00:11:32,000 --> 00:11:38,000
+If you don't remember what candidate K is this similar turn to alternate key?
+
+139
+00:11:38,000 --> 00:11:43,000
+Please review one more time lesson about basic terms in a relational databases.
+
+140
+00:11:44,000 --> 00:11:51,000
+Imagine that you have a table of users, and most likely you're going to have a column that will be
+
+141
+00:11:51,000 --> 00:11:55,000
+used as primary key and primary index for records in this table.
+
+142
+00:11:56,000 --> 00:12:02,000
+But you know that according to your business, logic user may be often requested by email.
+
+143
+00:12:03,000 --> 00:12:06,000
+That's why you decide to create one more index for email.
+
+144
+00:12:07,000 --> 00:12:13,000
+Email column contains also unique values and may be treated as candidate key.
+
+145
+00:12:13,000 --> 00:12:14,000
+Does it make sense?
+
+146
+00:12:15,000 --> 00:12:16,000
+Let me explain now.
+
+147
+00:12:16,000 --> 00:12:24,000
+Cluster Index If you all understood what's primary and secondary indexes are, it will be easier for
+
+148
+00:12:24,000 --> 00:12:26,000
+you to understand clustering index.
+
+149
+00:12:27,000 --> 00:12:33,000
+Imagine that you want to improve performance of reading the records, querying them by column that may
+
+150
+00:12:33,000 --> 00:12:35,000
+contain similar values and multiple rows.
+
+151
+00:12:36,000 --> 00:12:42,000
+For example, in the same scenario with users, in case you want to search user by their last name,
+
+152
+00:12:43,000 --> 00:12:47,000
+you should understand is it last name may not always be unique.
+
+153
+00:12:48,000 --> 00:12:56,000
+Z.Z Use Case of Clustering Index In order to identify the records first, it will look two or more columns
+
+154
+00:12:56,000 --> 00:13:00,000
+together to get the values and create index out of them.
+
+155
+00:13:00,000 --> 00:13:06,000
+Pay attention to this because it is critically important to have unique search query, and this is impossible
+
+156
+00:13:06,000 --> 00:13:09,000
+to create index on non unique values.
+
+157
+00:13:10,000 --> 00:13:16,000
+So you still would need to identify a combination of columns that will give you Zanik value for each
+
+158
+00:13:16,000 --> 00:13:19,000
+step and create index based on that.
+
+159
+00:13:19,000 --> 00:13:26,000
+This method is called a clustering index, basically records with similar characteristics and grouped
+
+160
+00:13:26,000 --> 00:13:29,000
+together, and indexes are created for these groups.
+
+161
+00:13:30,000 --> 00:13:34,000
+I believe they learned enough theory to jump the practice activities.
+
+162
+00:13:35,000 --> 00:13:39,000
+We're going to use our user tables that we created in previous lessons.
+
+163
+00:13:39,000 --> 00:13:42,000
+In case you don't know how to create a table.
+
+164
+00:13:42,000 --> 00:13:43,000
+Want to create a similar one?
+
+165
+00:13:44,000 --> 00:13:46,000
+Please make sure you watch the previous lesson.
+
+166
+00:13:47,000 --> 00:13:53,000
+When we created our first table and database do mouse, right click over the table and select Alter
+
+167
+00:13:53,000 --> 00:13:57,000
+Table Select Indexes set up here.
+
+168
+00:13:58,000 --> 00:14:03,000
+This is a tab that allows us to create, configure and remove indexes.
+
+169
+00:14:04,000 --> 00:14:11,000
+Each index has name to create new index, click in an empty row and time and a name.
+
+170
+00:14:11,000 --> 00:14:13,000
+After that, select in the start.
+
+171
+00:14:14,000 --> 00:14:16,000
+Let me review Is you each of this?
+
+172
+00:14:17,000 --> 00:14:18,000
+This is my SQL index types.
+
+173
+00:14:19,000 --> 00:14:26,000
+They're similar from the relational database theory that we have discussed, but definitely this ones
+
+174
+00:14:26,000 --> 00:14:29,000
+have specifics related to my school database management system.
+
+175
+00:14:29,000 --> 00:14:37,000
+Only primary index is created by default for each primary key, and you see the one was already created.
+
+176
+00:14:38,000 --> 00:14:42,000
+My school creates the index by default for primary key column.
+
+177
+00:14:43,000 --> 00:14:46,000
+You can click on existing index to explore the details.
+
+178
+00:14:47,000 --> 00:14:55,000
+For example, you can learn which column is used to create this index and column, or I send them all
+
+179
+00:14:55,000 --> 00:14:55,000
+this send.
+
+180
+00:14:56,000 --> 00:15:04,000
+In this time may be used for secondary indexes, that means that values in this column may not be unique.
+
+181
+00:15:05,000 --> 00:15:10,000
+For example, you can see that my school automatically created index for foreign key.
+
+182
+00:15:11,000 --> 00:15:12,000
+I didn't do that.
+
+183
+00:15:12,000 --> 00:15:14,000
+This was done by my school.
+
+184
+00:15:15,000 --> 00:15:19,000
+Unique index type created four columns was only unique values.
+
+185
+00:15:20,000 --> 00:15:24,000
+For example, you may have unique properties set for email column.
+
+186
+00:15:24,000 --> 00:15:28,000
+That means that it is possible to create unique index for this column.
+
+187
+00:15:28,000 --> 00:15:32,000
+To discuss reading operations from user table.
+
+188
+00:15:32,000 --> 00:15:36,000
+Using user email in search query will become faster.
+
+189
+00:15:36,000 --> 00:15:44,000
+Full text indexes are used for full text searches on in the BE and might use some storage engines,
+
+190
+00:15:44,000 --> 00:15:50,000
+support full text indexes and only for Char Bircher and text columns.
+
+191
+00:15:51,000 --> 00:15:56,000
+Indexing always takes place over the entire column and column preface.
+
+192
+00:15:57,000 --> 00:16:01,000
+Also, we can create indexes on spatial data types.
+
+193
+00:16:01,000 --> 00:16:10,000
+My Esam and in B supports our three indexes on special types as a search engines use matrix for index
+
+194
+00:16:10,000 --> 00:16:17,000
+and special types, except for archive, which doesn't support special type indexing.
+
+195
+00:16:19,000 --> 00:16:25,000
+On this slide, you can see the characteristics of different index types in energy B storage engine
+
+196
+00:16:25,000 --> 00:16:26,000
+of my school.
+
+197
+00:16:27,000 --> 00:16:31,000
+Each index also has a different set of properties.
+
+198
+00:16:31,000 --> 00:16:38,000
+Let's review each of them for string columns, indexes may use only as a leading part of column values
+
+199
+00:16:39,000 --> 00:16:40,000
+using blanks property.
+
+200
+00:16:41,000 --> 00:16:47,000
+This allows us to create index only for prefixes and other properties that can be used.
+
+201
+00:16:47,000 --> 00:16:55,000
+Here is a key block source for my use some tables Key block size optionally specifies the size in bytes
+
+202
+00:16:55,000 --> 00:16:57,000
+to use for index key blocks.
+
+203
+00:16:58,000 --> 00:17:03,000
+The value is treated as a hint and different size could be used if necessary.
+
+204
+00:17:04,000 --> 00:17:10,000
+Akeem Look Source value specified for an individual index definition overrides a table level key block
+
+205
+00:17:10,000 --> 00:17:11,000
+size value.
+
+206
+00:17:12,000 --> 00:17:15,000
+It is not supported at the index level for any DB tables.
+
+207
+00:17:16,000 --> 00:17:21,000
+Also only for full text indexes, you can specify parser.
+
+208
+00:17:22,000 --> 00:17:29,000
+It associates a person plug in with the index if full text indexing and search and operations need special
+
+209
+00:17:29,000 --> 00:17:34,000
+handling in London, B and My s some supports full text parser plugins.
+
+210
+00:17:34,000 --> 00:17:40,000
+If you are interested, you can find more information in official documentation of my SQL about full
+
+211
+00:17:40,000 --> 00:17:47,000
+text parser plugins for this specific case, I believe that topic lies outside of the scope of this
+
+212
+00:17:47,000 --> 00:17:48,000
+lesson.
+
+213
+00:17:48,000 --> 00:17:51,000
+Also, you can specify index visibility.
+
+214
+00:17:51,000 --> 00:17:53,000
+You have separate checkbox here.
+
+215
+00:17:54,000 --> 00:18:01,000
+You can place a tweak to make index visible and you can remove it take to make index invisible.
+
+216
+00:18:01,000 --> 00:18:04,000
+My cycle supports invisible indexes.
+
+217
+00:18:04,000 --> 00:18:08,000
+That is, indexes that are not used by the optimizer.
+
+218
+00:18:09,000 --> 00:18:13,000
+The feature applies to indexes, pauses and primary keys.
+
+219
+00:18:13,000 --> 00:18:18,000
+Using explicit or implicit indexes are visible by default.
+
+220
+00:18:19,000 --> 00:18:27,000
+After you configure it all what you need, just click apply button and execute generated SQL query to
+
+221
+00:18:27,000 --> 00:18:32,000
+remove indexes that you created, do most right click on the index and click Delete selected.
+
+222
+00:18:33,000 --> 00:18:33,000
+That's it.
+
+223
+00:18:34,000 --> 00:18:40,000
+By this moment in our lesson, I believe you already have both theoretical and practical understanding
+
+224
+00:18:40,000 --> 00:18:41,000
+of indexes.
+
+225
+00:18:42,000 --> 00:18:47,000
+And now we will be able to come up with advantages and disadvantages of indexes.
+
+226
+00:18:47,000 --> 00:18:48,000
+Together with me.
+
+227
+00:18:49,000 --> 00:18:55,000
+And one advantage advantages of indexing it is worth to mention the following once it helps to reduce
+
+228
+00:18:55,000 --> 00:19:02,000
+the total number of input output operations needed to retrieve that data offers faster search and retrieval
+
+229
+00:19:02,000 --> 00:19:03,000
+of data.
+
+230
+00:19:04,000 --> 00:19:10,000
+So we can say that performance of raid operations is increased and we shouldn't forget about the next
+
+231
+00:19:10,000 --> 00:19:19,000
+disadvantages additional disk memory space needed to store index decreased performance of write operations,
+
+232
+00:19:19,000 --> 00:19:27,000
+slower insert, update and delete operations because besides removal of trouble, it is also required
+
+233
+00:19:27,000 --> 00:19:30,000
+to recalculate index to keep it in sorted state.
+
+234
+00:19:31,000 --> 00:19:34,000
+That's all what I wanted to discuss with you today in this lesson.
+
+235
+00:19:34,000 --> 00:19:36,000
+Let's recap what we have learned today.
+
+236
+00:19:37,000 --> 00:19:41,000
+In this lesson, we have learned a lot of interesting things about indexes.
+
+237
+00:19:42,000 --> 00:19:44,000
+They learned what indexing database is.
+
+238
+00:19:45,000 --> 00:19:48,000
+I believe that you understood why we need indexes.
+
+239
+00:19:49,000 --> 00:19:54,000
+Also, I put separate focus on the details to help you understand how it works.
+
+240
+00:19:55,000 --> 00:20:03,000
+You also know what be tree data structure is and how logarithmic connotation of elements retrieval from
+
+241
+00:20:03,000 --> 00:20:07,000
+collection may be achieved via a view of different index types.
+
+242
+00:20:08,000 --> 00:20:11,000
+Those include primary secondary clustering.
+
+243
+00:20:11,000 --> 00:20:18,000
+I showed you how to create and remove indexes in database, and at the end of the lesson, we have reviewed
+
+244
+00:20:18,000 --> 00:20:21,000
+advantages and disadvantages of using indexes.
+
+245
+00:20:22,000 --> 00:20:23,000
+That's all for this lesson.
+
+246
+00:20:24,000 --> 00:20:26,000
+Thanks a lot for your attention, Tim.
+
+247
+00:20:26,000 --> 00:20:29,000
+Have a great day and see you in the next lesson.
+

47 - Relational databases/005 Database Normalization & Denormalization_en.srt

@@ -0,0 +1,1576 @@
+1
+00:00:06,000 --> 00:00:11,000
+Hello, yes, tenants in this lesson, we're going to learn more advanced concepts in the relational
+
+2
+00:00:11,000 --> 00:00:12,000
+databases.
+
+3
+00:00:12,000 --> 00:00:17,000
+We're going to talk about database normalization and normalization.
+
+4
+00:00:17,000 --> 00:00:20,000
+Believe me, this is a really important lesson.
+
+5
+00:00:20,000 --> 00:00:26,000
+And knowing the rules that I'm going to share with you in this lesson, you will be able to create scalable
+
+6
+00:00:26,000 --> 00:00:28,000
+database architecture.
+
+7
+00:00:28,000 --> 00:00:31,000
+And also, this will help you a lot in your career.
+
+8
+00:00:32,000 --> 00:00:37,000
+We are going to study the lesson from understanding of what data anomalies are.
+
+9
+00:00:38,000 --> 00:00:44,000
+I'm going to explain what insertion date and deletion anomaly is known as a problem.
+
+10
+00:00:44,000 --> 00:00:46,000
+We'll learn how to avoid it.
+
+11
+00:00:46,000 --> 00:00:53,000
+And after understanding of basics of dependency theory, we'll jump to our main topic today.
+
+12
+00:00:53,000 --> 00:00:59,000
+I'm talking about normalization and normal forms that we are going to review with examples.
+
+13
+00:00:59,000 --> 00:01:03,000
+Anthem's and obsolescent will discuss what the normalization is.
+
+14
+00:01:04,000 --> 00:01:05,000
+Let's start our lesson.
+
+15
+00:01:06,000 --> 00:01:12,000
+And before we even jump to discussion of what normalization is, let's understand what problem we have
+
+16
+00:01:12,000 --> 00:01:13,000
+learned to address.
+
+17
+00:01:13,000 --> 00:01:16,000
+Let me explain you what data anomalies are.
+
+18
+00:01:17,000 --> 00:01:24,000
+Data anomalies are inconsistencies in the data stored in the database as a result of an operation such
+
+19
+00:01:24,000 --> 00:01:27,000
+as update insertion and or deletion.
+
+20
+00:01:28,000 --> 00:01:34,000
+Such inconsistencies may arise when we have a particular records stored in multiple locations, and
+
+21
+00:01:34,000 --> 00:01:42,000
+not all of the corpus are updated generally and with relational database design must capture all of
+
+22
+00:01:42,000 --> 00:01:45,000
+the necessary attributes and associations.
+
+23
+00:01:46,000 --> 00:01:53,000
+The design should do this was a minimal amount of storage information and no redundant data in database
+
+24
+00:01:53,000 --> 00:01:54,000
+design.
+
+25
+00:01:54,000 --> 00:02:01,000
+Redundancy is generally undesirable because it causes problems maintaining consistency after updates.
+
+26
+00:02:02,000 --> 00:02:08,000
+We are going to learn such term as normalization later today, but I already can say that normalization
+
+27
+00:02:08,000 --> 00:02:14,000
+can help us to reduce data redundancy and minimize risks of data anomalies.
+
+28
+00:02:14,000 --> 00:02:18,000
+But sometimes we want to add data redundancy on purpose.
+
+29
+00:02:19,000 --> 00:02:26,000
+We need to do this carefully and was clear understanding of why we are doing this and what benefits
+
+30
+00:02:26,000 --> 00:02:27,000
+we expect to get.
+
+31
+00:02:28,000 --> 00:02:31,000
+Redundancy can sometimes leave the performance improvements.
+
+32
+00:02:32,000 --> 00:02:36,000
+We are going to discuss how this may improve our performance.
+
+33
+00:02:36,000 --> 00:02:41,000
+One will talk about the normalization Xen different, anomalous.
+
+34
+00:02:41,000 --> 00:02:42,000
+Let's review some of them.
+
+35
+00:02:43,000 --> 00:02:47,000
+I'm going to show different types of anomalies on example.
+
+36
+00:02:47,000 --> 00:02:49,000
+Let's look at this example first.
+
+37
+00:02:50,000 --> 00:02:53,000
+Imagine that we have a table with suppliers.
+
+38
+00:02:53,000 --> 00:02:59,000
+We also store information about them like address and products they produce.
+
+39
+00:02:59,000 --> 00:03:04,000
+There is also information about quantity of each product and its price.
+
+40
+00:03:04,000 --> 00:03:05,000
+Is that clear?
+
+41
+00:03:06,000 --> 00:03:08,000
+What do you think about this table?
+
+42
+00:03:08,000 --> 00:03:10,000
+Is it looks good to you.
+
+43
+00:03:11,000 --> 00:03:17,000
+Well, we're going to review in detail what is wrong in such kind of tables.
+
+44
+00:03:17,000 --> 00:03:20,000
+You already see huge data redundancy in this table.
+
+45
+00:03:21,000 --> 00:03:27,000
+Also, I believe we can notice is that the relationships between a key attribute and other data you
+
+46
+00:03:27,000 --> 00:03:29,000
+topple is not always logical.
+
+47
+00:03:30,000 --> 00:03:34,000
+Let me show you in detail what problems may be caused by this data redundancy.
+
+48
+00:03:35,000 --> 00:03:42,000
+And the first anomalies that we are going to learn is insertion anomaly imagines that we need that new
+
+49
+00:03:42,000 --> 00:03:42,000
+supplier.
+
+50
+00:03:43,000 --> 00:03:45,000
+We know its name.
+
+51
+00:03:45,000 --> 00:03:49,000
+We know it's address, but we don't know.
+
+52
+00:03:49,000 --> 00:03:51,000
+These are products that it produces.
+
+53
+00:03:51,000 --> 00:03:53,000
+No prices for these brothers.
+
+54
+00:03:53,000 --> 00:03:56,000
+We just started cooperation with them.
+
+55
+00:03:56,000 --> 00:03:58,000
+A company has been just registered.
+
+56
+00:03:59,000 --> 00:04:03,000
+And what should I put in product quantity and price columns?
+
+57
+00:04:03,000 --> 00:04:06,000
+I have to put empty, of course, data.
+
+58
+00:04:06,000 --> 00:04:09,000
+In this case, I have to base is a No.
+
+59
+00:04:10,000 --> 00:04:12,000
+Zero in different columns.
+
+60
+00:04:12,000 --> 00:04:13,000
+But is this correct?
+
+61
+00:04:14,000 --> 00:04:21,000
+Why I obligated to come up with values for columns that I don't need to use in this moment?
+
+62
+00:04:21,000 --> 00:04:29,000
+What if I just not aware about their products or why after companies established that was information
+
+63
+00:04:29,000 --> 00:04:30,000
+about their products?
+
+64
+00:04:30,000 --> 00:04:35,000
+If I just could add new rows was a product a lot of questions.
+
+65
+00:04:36,000 --> 00:04:42,000
+Another type of anomaly is update anomaly imagines that we decided to update supplier name.
+
+66
+00:04:43,000 --> 00:04:48,000
+Probably because of company reorganization, they decided to change their public name.
+
+67
+00:04:49,000 --> 00:04:56,000
+And now we need to execute the query to update all tables where we used suppliers name.
+
+68
+00:04:56,000 --> 00:05:01,000
+And we have really a lot of records where we need to accommodate supplier snake.
+
+69
+00:05:02,000 --> 00:05:10,000
+But what if we accidentally forgot it for some records during insertion, we added out, and for some
+
+70
+00:05:10,000 --> 00:05:10,000
+not.
+
+71
+00:05:11,000 --> 00:05:18,000
+What if accidentally SSEG different amount of space characters and some records still will be not updated?
+
+72
+00:05:18,000 --> 00:05:26,000
+In this case, I'm going to face that anomaly because after object, I will have inconsistent and not
+
+73
+00:05:26,000 --> 00:05:27,000
+valid data.
+
+74
+00:05:28,000 --> 00:05:30,000
+Do not accidentally forget the date throws.
+
+75
+00:05:30,000 --> 00:05:38,000
+It would be better if we could organize the restructure in a way when we have only one place where we
+
+76
+00:05:38,000 --> 00:05:43,000
+store supplier's name, then the risk of facing an added anomaly is minimal.
+
+77
+00:05:44,000 --> 00:05:46,000
+Let's have the deletion anomaly now.
+
+78
+00:05:47,000 --> 00:05:54,000
+This type of anomaly may occur when we remove information and together with it, or remove information
+
+79
+00:05:54,000 --> 00:05:55,000
+that shouldn't be removed.
+
+80
+00:05:56,000 --> 00:06:04,000
+For example, we stopped cooperation with one supplier or we need just to remove information about delivery.
+
+81
+00:06:04,000 --> 00:06:11,000
+And in case we remove information about delivery, we lose information about our supplier and vice versa.
+
+82
+00:06:12,000 --> 00:06:15,000
+All this information is important for our accounting department.
+
+83
+00:06:16,000 --> 00:06:20,000
+We also might need to use this information to create different reports.
+
+84
+00:06:21,000 --> 00:06:25,000
+What we should do in this case, it is hard question to answer.
+
+85
+00:06:26,000 --> 00:06:30,000
+Do you see what problems may be caused by data redundancy in our table?
+
+86
+00:06:30,000 --> 00:06:32,000
+How to fix this.
+
+87
+00:06:32,000 --> 00:06:39,000
+The best approach to create tables without anomalies is to ensure that the tables are normalized, and
+
+88
+00:06:39,000 --> 00:06:43,000
+that's accomplished by understanding functional dependencies.
+
+89
+00:06:43,000 --> 00:06:49,000
+Functional dependency ensures that all attributes in the table belong to that table.
+
+90
+00:06:50,000 --> 00:06:54,000
+In other words, it will eliminate redundancies and anomalies.
+
+91
+00:06:55,000 --> 00:07:02,000
+Let me show you as a solution for our example and what structure would help us to avoid the two anomalies.
+
+92
+00:07:02,000 --> 00:07:07,000
+Let's change our tables and create two tables instead of one.
+
+93
+00:07:08,000 --> 00:07:12,000
+We create supply a table and also a great delivery table.
+
+94
+00:07:13,000 --> 00:07:17,000
+In one table, we can store all information related to supply.
+
+95
+00:07:17,000 --> 00:07:23,000
+And in another table, we're going to store all information related to delivery.
+
+96
+00:07:23,000 --> 00:07:26,000
+And we establish relationships between these two tables.
+
+97
+00:07:27,000 --> 00:07:31,000
+So avoid data duplication, for example, for each delivery.
+
+98
+00:07:31,000 --> 00:07:33,000
+There is a specific supply.
+
+99
+00:07:33,000 --> 00:07:36,000
+Each supplier can have many deliveries.
+
+100
+00:07:37,000 --> 00:07:39,000
+Each delivery is provided by one supplier.
+
+101
+00:07:40,000 --> 00:07:45,000
+Is it clear we want to add information about is delivery or supply?
+
+102
+00:07:46,000 --> 00:07:52,000
+We are not obligated to add false information or information that we don't have in this moment.
+
+103
+00:07:53,000 --> 00:07:56,000
+No dummy values are needed during the insertion.
+
+104
+00:07:56,000 --> 00:08:04,000
+This resource, our insertion anomaly in the case, we want to add the name of supplier or its address.
+
+105
+00:08:04,000 --> 00:08:07,000
+We shouldn't do this in hundredths rose.
+
+106
+00:08:07,000 --> 00:08:14,000
+We do this in one place and the reference to the supply is still the same in delivery table in case
+
+107
+00:08:14,000 --> 00:08:19,000
+we want to remove information about delivery but don't want to remove information about supply.
+
+108
+00:08:20,000 --> 00:08:27,000
+We just do so we can do that both from delivery table without losing data from supply table.
+
+109
+00:08:27,000 --> 00:08:28,000
+Isn't this cool?
+
+110
+00:08:29,000 --> 00:08:35,000
+That's why, though, would this anomalous, you need to know what normalization is and its main rules.
+
+111
+00:08:36,000 --> 00:08:42,000
+But before starting to learn normal forms and normalization, we need to learn a little bit more theory
+
+112
+00:08:43,000 --> 00:08:49,000
+because you need to know at least some key concepts from dependencies theory in order you could understand
+
+113
+00:08:49,000 --> 00:08:57,000
+normalization dependency theory is a sub field of database theory, which status, implication and optimization
+
+114
+00:08:57,000 --> 00:09:02,000
+problems related to logical constraints, commonly called dependencies.
+
+115
+00:09:02,000 --> 00:09:10,000
+On that basis, the best known class of such dependencies are functional dependencies, which forms
+
+116
+00:09:10,000 --> 00:09:13,000
+the foundation of keys on database relations.
+
+117
+00:09:13,000 --> 00:09:18,000
+And in this lesson, we are going to review excerpts from dependency theory.
+
+118
+00:09:18,000 --> 00:09:19,000
+Let's start.
+
+119
+00:09:20,000 --> 00:09:26,000
+And as a result, you said one of the main concept in the theory is functional dependency.
+
+120
+00:09:27,000 --> 00:09:34,000
+Financial dependency tells us that if we have two attributes X and Y of some relationship, then wise
+
+121
+00:09:34,000 --> 00:09:45,000
+functional dependence on X if in any moment of time each X value matches, only one y value X is set
+
+122
+00:09:45,000 --> 00:09:47,000
+to functionally determine Y.
+
+123
+00:09:48,000 --> 00:09:54,000
+Functional dependency is a constraint between two sets of attributes in the relation from a database,
+
+124
+00:09:55,000 --> 00:10:03,000
+for example, bus number and last name of the person employee and his corporate email.
+
+125
+00:10:03,000 --> 00:10:10,000
+We can say that there is a functional dependency between these attributes is the determination of functional
+
+126
+00:10:10,000 --> 00:10:17,000
+dependencies is an important part of designing databases in a relational model and in database standardization
+
+127
+00:10:17,000 --> 00:10:19,000
+and generalization.
+
+128
+00:10:19,000 --> 00:10:26,000
+This is important to understand because during the normalization of our tables will investigate functional
+
+129
+00:10:26,000 --> 00:10:32,000
+dependencies between attributes, and it is crucial to identify which attributes that's in mind as the
+
+130
+00:10:32,000 --> 00:10:33,000
+ones.
+
+131
+00:10:34,000 --> 00:10:37,000
+Now, let's understand some more details.
+
+132
+00:10:37,000 --> 00:10:45,000
+Functional dependency between X and Y may be called complete functional dependency and Case Y is determined
+
+133
+00:10:45,000 --> 00:10:47,000
+by all subset of X.
+
+134
+00:10:47,000 --> 00:10:54,000
+And again, I'm trying to simplify these concepts as much as they can, because in cuz I would tell
+
+135
+00:10:54,000 --> 00:10:58,000
+you definition from Wikipedia, it wouldn't bring more sense.
+
+136
+00:10:59,000 --> 00:11:06,000
+For example, imagine that you have subsets of attributes like place of dispatch delivery, destination
+
+137
+00:11:06,000 --> 00:11:08,000
+type of cargo, cargo weight.
+
+138
+00:11:09,000 --> 00:11:12,000
+All these attributes determine price of delivery.
+
+139
+00:11:12,000 --> 00:11:13,000
+I agree.
+
+140
+00:11:14,000 --> 00:11:20,000
+You can easily check this by removing any attribute from the subset and check whether the relationship
+
+141
+00:11:20,000 --> 00:11:28,000
+is still valid because in case of cargo weight from subset of attributes, then the total price of delivery
+
+142
+00:11:28,000 --> 00:11:29,000
+will be completely different.
+
+143
+00:11:30,000 --> 00:11:36,000
+That's how easily I can check and ensure that there is complete functional dependency between set of
+
+144
+00:11:36,000 --> 00:11:38,000
+judgments and another attribute.
+
+145
+00:11:39,000 --> 00:11:39,000
+Does it make sense?
+
+146
+00:11:40,000 --> 00:11:46,000
+And last but not the least important thing I'd like you to know about functional dependency is clear
+
+147
+00:11:46,000 --> 00:11:49,000
+understanding of transitive dependency.
+
+148
+00:11:49,000 --> 00:11:50,000
+Let me explain.
+
+149
+00:11:51,000 --> 00:12:00,000
+Functional dependency X from Y may be called transitive if dependencies between X and Z and Z and Y,
+
+150
+00:12:01,000 --> 00:12:07,000
+but there is no direct dependency between X and Y, and this case dependency will be called transitive.
+
+151
+00:12:08,000 --> 00:12:14,000
+For example, there might be dependency between idea of employee and the DH of office, whereas this
+
+152
+00:12:14,000 --> 00:12:21,000
+employee works and there is another dependency between Officer NI and number of whom is that office.
+
+153
+00:12:22,000 --> 00:12:27,000
+So that means is a dependency between ideal employee and his office.
+
+154
+00:12:27,000 --> 00:12:28,000
+Phone number is transitive.
+
+155
+00:12:29,000 --> 00:12:29,000
+Is it clear?
+
+156
+00:12:31,000 --> 00:12:33,000
+Now, when we know what functional dependence it is.
+
+157
+00:12:33,000 --> 00:12:37,000
+Well, good to proceed with learning of normalization and normal forms.
+
+158
+00:12:38,000 --> 00:12:44,000
+Let's understand first what is normalization that at least normalization is a process of structure.
+
+159
+00:12:44,000 --> 00:12:52,000
+The database usually a relational database in accordance with serious of so-called normal forms in order
+
+160
+00:12:52,000 --> 00:12:56,000
+to reduce data redundancy and improve data integrity.
+
+161
+00:12:57,000 --> 00:13:02,000
+It was first proposed by Andrew Card as a part of his relational model.
+
+162
+00:13:03,000 --> 00:13:06,000
+That the definition of database normalization may sound like this.
+
+163
+00:13:07,000 --> 00:13:13,000
+Naming normalization is grouping and or distribution of attributes between different relationships to
+
+164
+00:13:13,000 --> 00:13:21,000
+eliminate data anomalies during their operations was database guarantee and data integrity and consistency
+
+165
+00:13:22,000 --> 00:13:23,000
+and optimization of DB.
+
+166
+00:13:24,000 --> 00:13:29,000
+In the definition of normalization, we use such term as normal forms.
+
+167
+00:13:30,000 --> 00:13:31,000
+What are normal forms?
+
+168
+00:13:32,000 --> 00:13:39,000
+A normal form is a property of a relationship in the relational data model that describes it from the
+
+169
+00:13:39,000 --> 00:13:45,000
+point of redundancy that can potentially lead to mistakes during the data insertion reading written
+
+170
+00:13:46,000 --> 00:13:47,000
+data deletion.
+
+171
+00:13:48,000 --> 00:13:54,000
+You already know about data anomalies and the other you saw examples based on this.
+
+172
+00:13:54,000 --> 00:13:59,000
+I make a conclusion that you understand our motivation to learn normal forms.
+
+173
+00:14:00,000 --> 00:14:02,000
+There are different normal forms.
+
+174
+00:14:02,000 --> 00:14:04,000
+We can say that three of them.
+
+175
+00:14:04,000 --> 00:14:05,000
+I mean, once.
+
+176
+00:14:06,000 --> 00:14:12,000
+But we also learn to hold an overview of different normal forms in this lesson to help you understand
+
+177
+00:14:12,000 --> 00:14:13,000
+this topic better.
+
+178
+00:14:14,000 --> 00:14:19,000
+We're going to review normal forms from the least normalized to most normalized.
+
+179
+00:14:20,000 --> 00:14:25,000
+In the other based harmonization and normalized form, it is also maybe referred as you, NF.
+
+180
+00:14:26,000 --> 00:14:31,000
+Also known as normalized relation or non first normal form.
+
+181
+00:14:31,000 --> 00:14:38,000
+This is a database data model which does meet any of the conditions of database normalization defined
+
+182
+00:14:38,000 --> 00:14:39,000
+by the relational model.
+
+183
+00:14:40,000 --> 00:14:48,000
+Database systems, which supports a normalized data, is sometimes called non relational or no SQL databases
+
+184
+00:14:48,000 --> 00:14:54,000
+in the relational model and normalized relations can be considered a starting point for a process of
+
+185
+00:14:54,000 --> 00:14:55,000
+normalization.
+
+186
+00:14:56,000 --> 00:15:02,000
+It should not be confused with the normalization when normalization is deliberately compromised for
+
+187
+00:15:02,000 --> 00:15:06,000
+selected tables in relational database normalization.
+
+188
+00:15:06,000 --> 00:15:12,000
+The first form requires initial data to be viewed as relations in database systems.
+
+189
+00:15:12,000 --> 00:15:14,000
+Relations are represented as tables.
+
+190
+00:15:15,000 --> 00:15:19,000
+The relation view implies some constraints on the tables.
+
+191
+00:15:20,000 --> 00:15:25,000
+No duplicates Ross Combs have unique names was in the same table.
+
+192
+00:15:25,000 --> 00:15:30,000
+Each column has data type, which defines allowed values in the column.
+
+193
+00:15:31,000 --> 00:15:34,000
+All rows in table have the same set of columns.
+
+194
+00:15:35,000 --> 00:15:36,000
+As you can see.
+
+195
+00:15:36,000 --> 00:15:40,000
+Most of the requirements are familiar to us and seems to be logical.
+
+196
+00:15:40,000 --> 00:15:46,000
+But from the theoretical point of view, this is just a starting point following normalization, and
+
+197
+00:15:46,000 --> 00:15:50,000
+the requirement is it should be mapped before we start applying even first normal form.
+
+198
+00:15:51,000 --> 00:15:54,000
+You can see an example of a normalized form on the slide.
+
+199
+00:15:55,000 --> 00:16:01,000
+This table represents a relation where transactions column is itself relation value.
+
+200
+00:16:01,000 --> 00:16:08,000
+This is relative relation but doesn't conform to first normal form, which doesn't allow nested relations.
+
+201
+00:16:09,000 --> 00:16:12,000
+The table is therefore a normalized.
+
+202
+00:16:12,000 --> 00:16:15,000
+If this is clear, then let's move on.
+
+203
+00:16:16,000 --> 00:16:19,000
+Let's see it was done in a basic normal form.
+
+204
+00:16:19,000 --> 00:16:23,000
+The first normal form relation is in the first normal form.
+
+205
+00:16:23,000 --> 00:16:32,000
+If and only if, no attribute domain has relations as elements or more informally, that no table column
+
+206
+00:16:32,000 --> 00:16:34,000
+can have tables as values.
+
+207
+00:16:35,000 --> 00:16:41,000
+But this definition tells us that the most relational databases already in the first normal form by
+
+208
+00:16:41,000 --> 00:16:45,000
+default because it is impossible to have table value in the relational database.
+
+209
+00:16:46,000 --> 00:16:50,000
+That's why I like another definition of the first normal form.
+
+210
+00:16:51,000 --> 00:16:58,000
+Relationship is in first normal form if and only if each its attribute is atomic.
+
+211
+00:16:58,000 --> 00:16:59,000
+What does it mean?
+
+212
+00:17:00,000 --> 00:17:01,000
+I told me catching it.
+
+213
+00:17:02,000 --> 00:17:08,000
+This means that in your business, to me and in business logic of application, there is no need to
+
+214
+00:17:08,000 --> 00:17:13,000
+extract on the specific parts of the attribute to perform some operation, was it?
+
+215
+00:17:14,000 --> 00:17:16,000
+Let me explain, is this on the example?
+
+216
+00:17:17,000 --> 00:17:21,000
+Imagine that you have supply a table and each supplier has its legal address.
+
+217
+00:17:22,000 --> 00:17:28,000
+This address contains Country City Street Building Office Number.
+
+218
+00:17:28,000 --> 00:17:35,000
+But what if your application needs to perform operations with suppliers based on their country location?
+
+219
+00:17:36,000 --> 00:17:43,000
+You need to be able to extract all supplies from Russia or all suppliers from India or Ukraine.
+
+220
+00:17:43,000 --> 00:17:47,000
+Or you say how you can do this with this data model.
+
+221
+00:17:48,000 --> 00:17:55,000
+The only way for you to do this is to extract as a whole address, then pass it inside the program and
+
+222
+00:17:55,000 --> 00:17:57,000
+take on the country well.
+
+223
+00:17:57,000 --> 00:18:02,000
+That's why we can say that this table violates the first normal form.
+
+224
+00:18:03,000 --> 00:18:06,000
+Domains are stable, meet requirements of the first normal form.
+
+225
+00:18:07,000 --> 00:18:09,000
+We need to introduce new columns in the table.
+
+226
+00:18:10,000 --> 00:18:16,000
+Let's have separate columns for country city street building and office number.
+
+227
+00:18:16,000 --> 00:18:22,000
+In this case, even when we need to extract suppliers for a specific city, we can do this easily by
+
+228
+00:18:22,000 --> 00:18:25,000
+using city attributes as a search parameter.
+
+229
+00:18:25,000 --> 00:18:30,000
+Now we can say that our table meets the requirements of the first normal form.
+
+230
+00:18:31,000 --> 00:18:34,000
+Now, it is time for the second normal form.
+
+231
+00:18:35,000 --> 00:18:40,000
+Revelation is in second normal form, if it fulfils is a following two requirements.
+
+232
+00:18:41,000 --> 00:18:46,000
+It is in first normal form and it doesn't have any non-prime attribute.
+
+233
+00:18:47,000 --> 00:18:51,000
+It is functioning dependent on any proper subset of any candidate.
+
+234
+00:18:51,000 --> 00:18:59,000
+Key of the relation and non-prime attribute of a relation is an attribute that is not part of any candidate
+
+235
+00:18:59,000 --> 00:19:00,000
+key of their relation.
+
+236
+00:19:01,000 --> 00:19:08,000
+In simple words, you have to store maintains a table that relates only to the current entity, but
+
+237
+00:19:08,000 --> 00:19:09,000
+not another one.
+
+238
+00:19:10,000 --> 00:19:16,000
+All attributes should depend on the whole primary key, especially if this is compound primary.
+
+239
+00:19:16,000 --> 00:19:23,000
+Key attributes should have complete functional dependency was the whole columns in compound key.
+
+240
+00:19:23,000 --> 00:19:26,000
+But not only on its part.
+
+241
+00:19:26,000 --> 00:19:32,000
+This might sound complicated at the beginning, but in real life it is much simpler than you think.
+
+242
+00:19:33,000 --> 00:19:35,000
+Let me show you this one example.
+
+243
+00:19:35,000 --> 00:19:38,000
+I believe it will be easier to understand.
+
+244
+00:19:38,000 --> 00:19:42,000
+Here's a table of items that we sell in our store.
+
+245
+00:19:42,000 --> 00:19:46,000
+We have category neat discount and product name.
+
+246
+00:19:46,000 --> 00:19:52,000
+There is compound primary key that consists from category and date from this table.
+
+247
+00:19:52,000 --> 00:19:58,000
+We can now discount that should be applied to goods from specific category at specific date.
+
+248
+00:19:59,000 --> 00:20:04,000
+I believe that based on my explanation, you already understood what is wrong here.
+
+249
+00:20:04,000 --> 00:20:08,000
+This gown depends only on the product category and date.
+
+250
+00:20:08,000 --> 00:20:14,000
+That said, there is no direct dependency between discount and specific product.
+
+251
+00:20:15,000 --> 00:20:18,000
+Product depends only on the quiet of the primary key.
+
+252
+00:20:19,000 --> 00:20:21,000
+I mean, only on the category.
+
+253
+00:20:21,000 --> 00:20:27,000
+There is a dependency between discount for products from specific categories at a particular date.
+
+254
+00:20:27,000 --> 00:20:33,000
+Does it make sense because in this case, we have data redundancy?
+
+255
+00:20:33,000 --> 00:20:36,000
+So what would be a solution here?
+
+256
+00:20:36,000 --> 00:20:42,000
+The solution here is to make sure that complete functional dependency exists between all attributes
+
+257
+00:20:43,000 --> 00:20:44,000
+and primary key.
+
+258
+00:20:44,000 --> 00:20:51,000
+In our case, product has functional dependency category, but not with category and date.
+
+259
+00:20:52,000 --> 00:20:56,000
+That's why we create two tables in the first table.
+
+260
+00:20:56,000 --> 00:21:00,000
+We are going to have information about discount for category in particular date.
+
+261
+00:21:00,000 --> 00:21:04,000
+And then the second table, we're going to store all products.
+
+262
+00:21:04,000 --> 00:21:08,000
+This will allow us to have cleaner DB architecture.
+
+263
+00:21:09,000 --> 00:21:15,000
+Let's learn certain amount form, and then the basic relation is set to meet certain normal form standards.
+
+264
+00:21:15,000 --> 00:21:22,000
+If all the I think it's function dependent on Sullivan's primary key without any transitive dependencies,
+
+265
+00:21:23,000 --> 00:21:29,000
+then Xenia of the third normal form is to not store data and tables that can be retrieved from other
+
+266
+00:21:29,000 --> 00:21:30,000
+table attributes.
+
+267
+00:21:31,000 --> 00:21:34,000
+Imagine that we have a table of two users at the university.
+
+268
+00:21:34,000 --> 00:21:36,000
+We have such columns.
+
+269
+00:21:36,000 --> 00:21:42,000
+I need less name, title, salary department and phone number.
+
+270
+00:21:42,000 --> 00:21:45,000
+Is this table in the third normal form?
+
+271
+00:21:45,000 --> 00:21:47,000
+I don't think so.
+
+272
+00:21:47,000 --> 00:21:49,000
+Let's try to visualize dependencies here.
+
+273
+00:21:50,000 --> 00:21:56,000
+Salary depends on the title only it doesn't depend on specific person.
+
+274
+00:21:57,000 --> 00:22:04,000
+Specific tutor has its own title and works in concrete department, and they don't have personal work
+
+275
+00:22:04,000 --> 00:22:10,000
+phone numbers you can contact with them using phone in the department.
+
+276
+00:22:10,000 --> 00:22:18,000
+That's why we can say that there are different transitive dependencies, for example, transitive dependency
+
+277
+00:22:18,000 --> 00:22:26,000
+between concrete tutor department where he or she works, and phone number there is transitive dependency
+
+278
+00:22:26,000 --> 00:22:28,000
+between phone number and tutor.
+
+279
+00:22:28,000 --> 00:22:29,000
+Is it clear?
+
+280
+00:22:30,000 --> 00:22:36,000
+To remove all transitive dependencies and make sure that all relations means a certain normal form.
+
+281
+00:22:36,000 --> 00:22:39,000
+Let's split this data between different tables.
+
+282
+00:22:39,000 --> 00:22:46,000
+We need to create three tables to achieve this cuter table was last name, title and deportment.
+
+283
+00:22:46,000 --> 00:22:53,000
+Title table was titled Name Unrelated Salary Department Table was its name and phone.
+
+284
+00:22:53,000 --> 00:22:56,000
+That's it for some of my students.
+
+285
+00:22:56,000 --> 00:22:58,000
+Nothing is changed as a first glance.
+
+286
+00:22:59,000 --> 00:23:05,000
+We just have more tables and the relationships between different tables rather than storing old data
+
+287
+00:23:05,000 --> 00:23:06,000
+in one table in one place.
+
+288
+00:23:07,000 --> 00:23:09,000
+And you need to understand me, correct?
+
+289
+00:23:09,000 --> 00:23:12,000
+Because you can store everything in one table.
+
+290
+00:23:12,000 --> 00:23:14,000
+This is even has its own name.
+
+291
+00:23:15,000 --> 00:23:16,000
+No sequel.
+
+292
+00:23:16,000 --> 00:23:23,000
+Just to let you know that this is also possible, but you would lose advantage is its relational database
+
+293
+00:23:23,000 --> 00:23:24,000
+is all for you.
+
+294
+00:23:24,000 --> 00:23:30,000
+If you opt for relational databases, you need to clearly understand what advantage you expect to get
+
+295
+00:23:30,000 --> 00:23:31,000
+from it.
+
+296
+00:23:31,000 --> 00:23:39,000
+That's why the rule of thumb is to follow normal forms called later realized that certain normal form
+
+297
+00:23:39,000 --> 00:23:46,000
+did not eliminate all undesirable data anomalies and developed a strong aversion to address this in
+
+298
+00:23:46,000 --> 00:23:51,000
+1974, known as voice called normal form.
+
+299
+00:23:51,000 --> 00:23:56,000
+To be honest, yeah, many other normal forms on top of these that we have just discussed.
+
+300
+00:23:57,000 --> 00:24:03,000
+But in my opinion, this three as the most important ones, I'm still going to make a quick overview
+
+301
+00:24:03,000 --> 00:24:05,000
+of other normal forms, at least on the high level.
+
+302
+00:24:06,000 --> 00:24:12,000
+In case you would be interested in more detailed explanation of all other normal forms, we don't just
+
+303
+00:24:12,000 --> 00:24:16,000
+have any question related to normal forms reviewed in this lesson.
+
+304
+00:24:16,000 --> 00:24:21,000
+Please ask me in the comments below this video, and I will be happy to answer you.
+
+305
+00:24:22,000 --> 00:24:27,000
+Elementary Queen Normal fall is a subtle enhancement on certain minimal form.
+
+306
+00:24:27,000 --> 00:24:32,000
+Thus, E K and AV tables are insert normal form by definition.
+
+307
+00:24:33,000 --> 00:24:38,000
+This happens when there is more than one unique compound key, and they overlap.
+
+308
+00:24:39,000 --> 00:24:43,000
+Such cases can, of course, redundant information in the overlapping columns.
+
+309
+00:24:44,000 --> 00:24:52,000
+A table is an elementary key normal form if and only if all its elementary functional dependencies begin
+
+310
+00:24:52,000 --> 00:24:56,000
+at whole keys or and elementary key attributes.
+
+311
+00:24:57,000 --> 00:25:04,000
+Voice called normal form is slightly stronger version of the third normal form if relational schema
+
+312
+00:25:04,000 --> 00:25:10,000
+is in the called normal form zone, all redundancy based on functional dependency has been removed.
+
+313
+00:25:11,000 --> 00:25:14,000
+Also, other types of redundancy may still exist.
+
+314
+00:25:15,000 --> 00:25:22,000
+Force normal form is concerned was a more general type of dependency known as mutually dependency.
+
+315
+00:25:23,000 --> 00:25:31,000
+A table is enforced normal form if and only if, for every one of its non-travel lots of other dependencies.
+
+316
+00:25:31,000 --> 00:25:39,000
+X y x is a super key that is X. This is a candidate key or a superset zero.
+
+317
+00:25:41,000 --> 00:25:47,000
+Essential double normal form for relations is a relational database where the constraints are given
+
+318
+00:25:47,000 --> 00:25:50,000
+by functional dependencies and joint dependencies.
+
+319
+00:25:51,000 --> 00:25:58,000
+It lies strictly between first and fourth and fifth normal for our relations schema is an essential
+
+320
+00:25:58,000 --> 00:26:07,000
+double normal form if and only if it is invoiced called normal form and some component of every explicitly
+
+321
+00:26:07,000 --> 00:26:12,000
+declared during the pendency of the schema is a superkick thief's normal form.
+
+322
+00:26:13,000 --> 00:26:15,000
+Also known as project joined.
+
+323
+00:26:15,000 --> 00:26:22,000
+Normal form is a level of database normalization designed to reduce redundancy in relational databases,
+
+324
+00:26:22,000 --> 00:26:29,000
+recording multivariate facts but isolate and semantically related to multiple relationships.
+
+325
+00:26:29,000 --> 00:26:37,000
+A table is set to be in the fifth normal form if and only if every non-trivial joint dependency in that
+
+326
+00:26:37,000 --> 00:26:40,000
+table is implied by the candidate keys.
+
+327
+00:26:41,000 --> 00:26:49,000
+The main key normal form is a normal form used in database normalization, which requires the database
+
+328
+00:26:49,000 --> 00:26:56,000
+contains no constraints, Aussies and domain constraints and key constraints and domain constraints
+
+329
+00:26:56,000 --> 00:26:59,000
+insofar as a permissible values for a given attribute.
+
+330
+00:27:00,000 --> 00:27:07,000
+While a key constraint specifies is, it attributes that uniquely identify a role in a given table.
+
+331
+00:27:08,000 --> 00:27:15,000
+The new key normal form is achieved when every constraint on the relation is a logical consequence of
+
+332
+00:27:15,000 --> 00:27:21,000
+the definition of keys and the means and enforcing key and the main, the restraints and conditions
+
+333
+00:27:22,000 --> 00:27:24,000
+causes all constraints to be met.
+
+334
+00:27:24,000 --> 00:27:28,000
+Thus, it avoids all non temporal anomalies.
+
+335
+00:27:29,000 --> 00:27:29,000
+Six.
+
+336
+00:27:29,000 --> 00:27:38,000
+Normal form is intended to decompose relation variables to irreducible components, though this may
+
+337
+00:27:38,000 --> 00:27:41,000
+be relatively unimportant for non temporal relation variables.
+
+338
+00:27:42,000 --> 00:27:48,000
+It can be important when dealing with temporal variables or other internal data.
+
+339
+00:27:48,000 --> 00:27:57,000
+A table is in six normal form if and only if it satisfies no non-trivial joint dependencies at all.
+
+340
+00:27:57,000 --> 00:28:05,000
+Where, as before and during dependencies is trivial if and only if at least one of the projections
+
+341
+00:28:05,000 --> 00:28:10,000
+involved is taken over a set of all attributes of the table concerned.
+
+342
+00:28:11,000 --> 00:28:18,000
+As you see from high level overview, it might be not so easy to understand the practical need and value
+
+343
+00:28:18,000 --> 00:28:22,000
+of each of these normal forms to know how to apply.
+
+344
+00:28:22,000 --> 00:28:26,000
+Those probably separate lesson is needed for each.
+
+345
+00:28:26,000 --> 00:28:32,000
+But considering the fact that they are not so popular in comparison with the first three normal forms,
+
+346
+00:28:32,000 --> 00:28:35,000
+probably I will not cover them in detail in this lesson.
+
+347
+00:28:36,000 --> 00:28:43,000
+I strongly recommend you to apply first three normal forms during database architecture and during creation
+
+348
+00:28:43,000 --> 00:28:44,000
+of each table.
+
+349
+00:28:44,000 --> 00:28:50,000
+I might add, means that knowing of all other normal forms by heart is not so critical.
+
+350
+00:28:50,000 --> 00:28:56,000
+On the slide, you can see comparative analysis and the last, but not the least, things that I wanted
+
+351
+00:28:56,000 --> 00:28:59,000
+to discuss with you today is the normalization.
+
+352
+00:29:00,000 --> 00:29:07,000
+No normalization is a strategy used on the previously normalized database to increase performance in
+
+353
+00:29:07,000 --> 00:29:07,000
+computing.
+
+354
+00:29:07,000 --> 00:29:14,000
+The normalization is a process of trying to improve the performance of a database and the expense of
+
+355
+00:29:14,000 --> 00:29:20,000
+losing some light performance by adding redundant corpus of data all by group and later.
+
+356
+00:29:21,000 --> 00:29:27,000
+The normalization difference from a normalized form means that the normalization benefits can only be
+
+357
+00:29:27,000 --> 00:29:32,000
+fully realized on the data model that is otherwise normalized.
+
+358
+00:29:33,000 --> 00:29:35,000
+So how we can improve performance.
+
+359
+00:29:36,000 --> 00:29:43,000
+Imagine that we have multiple tables, we have table with soccer clubs, we have a table with soccer
+
+360
+00:29:43,000 --> 00:29:50,000
+leagues and we have table was match data that should contain information about me, home team and guests.
+
+361
+00:29:52,000 --> 00:29:55,000
+We also saw a lot of other information about teams and matches.
+
+362
+00:29:56,000 --> 00:30:04,000
+Now imagine that to extract much data for the home, the week moments, we need to query suite tables
+
+363
+00:30:04,000 --> 00:30:06,000
+and database for each row.
+
+364
+00:30:06,000 --> 00:30:11,000
+We may have spouses of matches and not only soccer.
+
+365
+00:30:11,000 --> 00:30:18,000
+I simplified the original example a bit, but imagine that you have multiple sports and you have teams
+
+366
+00:30:18,000 --> 00:30:21,000
+and different sports and much more leagues.
+
+367
+00:30:21,000 --> 00:30:25,000
+This is literally crazy amount of data each day.
+
+368
+00:30:25,000 --> 00:30:33,000
+Making Junqueras findings and mappings in different tables may take some time, while it might be not
+
+369
+00:30:33,000 --> 00:30:36,000
+so dramatic while querying a few records.
+
+370
+00:30:36,000 --> 00:30:44,000
+It is different when you query a lot of records, and that is a day we are receiving benefits by certain
+
+371
+00:30:44,000 --> 00:30:47,000
+entities in different tables without any duplication.
+
+372
+00:30:48,000 --> 00:30:55,000
+But when you query Susan's rose and do join requests with different tables, this might take some time
+
+373
+00:30:56,000 --> 00:31:00,000
+and to save time by not comparing other tables to get data you need.
+
+374
+00:31:00,000 --> 00:31:08,000
+We at data redundancy on purpose and understand know how better performance of reading operations is
+
+375
+00:31:08,000 --> 00:31:08,000
+achieved.
+
+376
+00:31:09,000 --> 00:31:17,000
+Imagine you need to read all matches, data in normalized database and you query in different tables
+
+377
+00:31:17,000 --> 00:31:25,000
+and you normalize database, you request all data from one place, then distanza mean a year of generalization.
+
+378
+00:31:26,000 --> 00:31:30,000
+But remember, this is something what should be done super carefully.
+
+379
+00:31:30,000 --> 00:31:37,000
+You need to be sure what benefits you will get from generalization, and it is recommended to be specific
+
+380
+00:31:37,000 --> 00:31:38,000
+in order.
+
+381
+00:31:38,000 --> 00:31:44,000
+You could understand how many seconds you would win in performance after the normalization.
+
+382
+00:31:44,000 --> 00:31:50,000
+I did this several times in my own projects, and I can say that this is a technique that's really worth
+
+383
+00:31:50,000 --> 00:31:53,000
+of your attention if you are going to use a smart.
+
+384
+00:31:54,000 --> 00:31:57,000
+That's all what I wanted to share with you in this lesson.
+
+385
+00:31:57,000 --> 00:32:01,000
+Let's recap what we have learned to date in this lesson.
+
+386
+00:32:01,000 --> 00:32:08,000
+You've learned what data anomalies are we have learned in session update and deletion anomalies.
+
+387
+00:32:09,000 --> 00:32:12,000
+Also, we reviewed the main concept in dependencies theory.
+
+388
+00:32:13,000 --> 00:32:17,000
+Now you know what a complete, unknown, complete functional dependency is.
+
+389
+00:32:18,000 --> 00:32:26,000
+After that, we learned what normalization is on examples of used normal forms and incentives was lesson
+
+390
+00:32:26,000 --> 00:32:27,000
+I explained.
+
+391
+00:32:27,000 --> 00:32:30,000
+What generalization is that?
+
+392
+00:32:30,000 --> 00:32:31,000
+So for this lesson?
+
+393
+00:32:31,000 --> 00:32:32,000
+Thanks a lot for your attention.
+
+394
+00:32:33,000 --> 00:32:35,000
+Have a great day and see you in the next lesson.
+

48 - SQL/001 MySQL-Documentation-about-statements.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://dev.mysql.com/doc/refman/8.0/en/create-view.html

48 - SQL/001 Query-Examples-that-were-shown-in-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/ddl

48 - SQL/001 SQL General Overview & DDL_en.srt

@@ -0,0 +1,976 @@
+1
+00:00:05,000 --> 00:00:06,000
+Hello, Kim.
+
+2
+00:00:06,000 --> 00:00:12,000
+Today, we're going to have a very important lesson in the lesson we are going to learn the basics of
+
+3
+00:00:12,000 --> 00:00:13,000
+structured query language.
+
+4
+00:00:14,000 --> 00:00:18,000
+I'm going to explain you what it is and why it is important to know it.
+
+5
+00:00:19,000 --> 00:00:22,000
+The work was databases will start from the very basics.
+
+6
+00:00:23,000 --> 00:00:25,000
+We'll learn what skill is in general.
+
+7
+00:00:26,000 --> 00:00:30,000
+And after that, we'll focus on data, definition, language and skill.
+
+8
+00:00:31,000 --> 00:00:35,000
+Don't worry, we'll not have only one lesson about sequel.
+
+9
+00:00:35,000 --> 00:00:38,000
+Still, there will be other lessons to learn.
+
+10
+00:00:38,000 --> 00:00:44,000
+But today we're going to build a basement for our further learning in the lesson we're going to learn
+
+11
+00:00:44,000 --> 00:00:45,000
+what sequel is.
+
+12
+00:00:45,000 --> 00:00:47,000
+I will explain what sequels have.
+
+13
+00:00:47,000 --> 00:00:48,000
+Languages are.
+
+14
+00:00:49,000 --> 00:00:52,000
+This will give you insights on what we are going to learn in this course.
+
+15
+00:00:53,000 --> 00:00:58,000
+After holding an overview of sequel language, we'll jump to learning of the first sequel.
+
+16
+00:00:58,000 --> 00:01:04,000
+Sub Language will learn data definition language in this video will review different statements with
+
+17
+00:01:04,000 --> 00:01:08,000
+great alter, rename, truncate and drop statements.
+
+18
+00:01:09,000 --> 00:01:16,000
+Also on the real examples you are going to see how we can create these statements and execute them against
+
+19
+00:01:16,000 --> 00:01:17,000
+our database.
+
+20
+00:01:17,000 --> 00:01:18,000
+Enough docs.
+
+21
+00:01:19,000 --> 00:01:22,000
+US start our lesson and to start our lesson.
+
+22
+00:01:22,000 --> 00:01:26,000
+Let's understand what sequel is and what we are going to learn in this course.
+
+23
+00:01:27,000 --> 00:01:29,000
+Sequel stands for structured query language.
+
+24
+00:01:30,000 --> 00:01:36,000
+It is the main specific language used to manage data held in the relational database management system.
+
+25
+00:01:36,000 --> 00:01:42,000
+Sequel was one of the first commercial languages to use anger cause relational model.
+
+26
+00:01:43,000 --> 00:01:50,000
+The model was described in his influential 1970 paper, a relational model of data for large shared
+
+27
+00:01:51,000 --> 00:01:51,000
+data banks.
+
+28
+00:01:52,000 --> 00:02:00,000
+Despite not entirely adhering to the relational model as described by code, it became most widely used.
+
+29
+00:02:00,000 --> 00:02:03,000
+Database language sequel became a standard.
+
+30
+00:02:03,000 --> 00:02:09,000
+Often, the American National Standards Institute in nineteen eighty six and all was the International
+
+31
+00:02:09,000 --> 00:02:13,000
+Organization for Standardization in 1987.
+
+32
+00:02:13,000 --> 00:02:19,000
+And because standardization of sequel wasn't done since its creation defines relational database management
+
+33
+00:02:19,000 --> 00:02:22,000
+systems invented their own differences.
+
+34
+00:02:22,000 --> 00:02:29,000
+Despite the existence of standards, most sequel code requires at least some minor changes before being
+
+35
+00:02:29,000 --> 00:02:31,000
+ported to different database systems.
+
+36
+00:02:32,000 --> 00:02:39,000
+So SQL itself is set of operators that allow us to interact with database management system, query
+
+37
+00:02:39,000 --> 00:02:42,000
+data in it and perform other operations.
+
+38
+00:02:43,000 --> 00:02:49,000
+These different statements and operators informally can be grouped and classified as different sublineages.
+
+39
+00:02:50,000 --> 00:02:58,000
+Ziya Data Definition Language It is a syntax for creating and modifying database objects such as tables,
+
+40
+00:02:58,000 --> 00:03:06,000
+indexes, etc. DDL statements are similar to a computer programming language for defining data structures,
+
+41
+00:03:06,000 --> 00:03:09,000
+especially database schemas.
+
+42
+00:03:09,000 --> 00:03:14,000
+Common examples of these statements include create, alter and draw.
+
+43
+00:03:15,000 --> 00:03:22,000
+Data manipulation language, is this a set of statements that they used for adding deleting dating data
+
+44
+00:03:22,000 --> 00:03:23,000
+in a database?
+
+45
+00:03:23,000 --> 00:03:27,000
+Common examples of these misstatements include select insert.
+
+46
+00:03:27,000 --> 00:03:29,000
+Update Delete.
+
+47
+00:03:30,000 --> 00:03:37,000
+Data control language, it is a syntax that is used to control access to data stored in a database.
+
+48
+00:03:37,000 --> 00:03:42,000
+Examples of this sale include grant and revoke statements.
+
+49
+00:03:43,000 --> 00:03:47,000
+And last but not least siblings, which is transaction control language.
+
+50
+00:03:47,000 --> 00:03:53,000
+This language group statements to manage transactions in databases and one examples of this.
+
+51
+00:03:53,000 --> 00:03:57,000
+It is worth to mention commit, rollback and safe points.
+
+52
+00:03:58,000 --> 00:04:05,000
+Based on this, we can make a conclusion that the scope of sequel includes data query, data manipulation,
+
+53
+00:04:05,000 --> 00:04:13,000
+data definition, data access control, transaction management and managing database objects in our
+
+54
+00:04:13,000 --> 00:04:14,000
+course on real examples.
+
+55
+00:04:14,000 --> 00:04:18,000
+We are going to learn how to work with different groups of statements.
+
+56
+00:04:19,000 --> 00:04:19,000
+OK.
+
+57
+00:04:20,000 --> 00:04:25,000
+I believe that now you understand what a sequel is and what we are going to learn.
+
+58
+00:04:25,000 --> 00:04:32,000
+And as we announced an agenda of this meeting, let's start learning the deal now and we will start
+
+59
+00:04:32,000 --> 00:04:33,000
+from the first statement.
+
+60
+00:04:34,000 --> 00:04:35,000
+It is a great statement.
+
+61
+00:04:36,000 --> 00:04:42,000
+The general structure of statement is the following you write create first.
+
+62
+00:04:42,000 --> 00:04:49,000
+After that, you specify what you want to create, whether it is a database schema to move you index.
+
+63
+00:04:50,000 --> 00:04:56,000
+After that, you put name of the database object that you want to create and optionally you can put
+
+64
+00:04:56,000 --> 00:04:57,000
+different options.
+
+65
+00:04:58,000 --> 00:04:59,000
+Let's review a few queries with you.
+
+66
+00:05:00,000 --> 00:05:03,000
+Degrade database We need to use the following construct.
+
+67
+00:05:04,000 --> 00:05:06,000
+We start from create keywords.
+
+68
+00:05:06,000 --> 00:05:10,000
+After that, we indicate that we want to create a database.
+
+69
+00:05:11,000 --> 00:05:19,000
+And by the way, in my school you can use both options is a create schema or create database.
+
+70
+00:05:19,000 --> 00:05:20,000
+They are similar.
+
+71
+00:05:21,000 --> 00:05:24,000
+After that, we need to specify name of the database.
+
+72
+00:05:24,000 --> 00:05:29,000
+Usually in sequel, we use single quotes for all string values.
+
+73
+00:05:30,000 --> 00:05:33,000
+That's why I put the name of our DB in quotes.
+
+74
+00:05:34,000 --> 00:05:37,000
+Basically, this is enough to create a database.
+
+75
+00:05:38,000 --> 00:05:41,000
+But additionally, we can add more sinks in the statement.
+
+76
+00:05:42,000 --> 00:05:48,000
+We can add a condition to make sure that we wouldn't even try to create a table if it exists already
+
+77
+00:05:49,000 --> 00:05:49,000
+for this.
+
+78
+00:05:49,000 --> 00:05:57,000
+Optionally, we can add, if not exist and the different create options that can be specified separately.
+
+79
+00:05:58,000 --> 00:06:03,000
+For example, you know that sometimes we also want to specify charset and collation.
+
+80
+00:06:03,000 --> 00:06:09,000
+You can write default character set, followed by Charsadda, that you want to use.
+
+81
+00:06:09,000 --> 00:06:15,000
+And after that, you can write code and specify collation that will be used for this charset.
+
+82
+00:06:16,000 --> 00:06:20,000
+Now this is complete query to be executed against database.
+
+83
+00:06:21,000 --> 00:06:26,000
+Let me start sharing my screen to execute this query together with you.
+
+84
+00:06:26,000 --> 00:06:31,000
+I'm going to show you how you can execute cycle queries from my SQL workbench.
+
+85
+00:06:32,000 --> 00:06:37,000
+If you don't have my SQL server installed and also you don't have my SQL workbench in your computer,
+
+86
+00:06:38,000 --> 00:06:44,000
+please refer to the previous classes where we together installed all required applications for my school
+
+87
+00:06:44,000 --> 00:06:46,000
+relational database management system.
+
+88
+00:06:47,000 --> 00:06:52,000
+You can execute any SQL query you wish directly from sequel editor.
+
+89
+00:06:53,000 --> 00:07:00,000
+Just click on this icon that is called Create New SQL tab for executing queries and Knewthat will be
+
+90
+00:07:00,000 --> 00:07:01,000
+opened.
+
+91
+00:07:01,000 --> 00:07:07,000
+Now you can type any query you wish can save time during this video lesson.
+
+92
+00:07:07,000 --> 00:07:12,000
+I already pasted here's a query removed to create a database.
+
+93
+00:07:12,000 --> 00:07:17,000
+Press a pause for a few seconds if you need to times square it in a sequel editor.
+
+94
+00:07:18,000 --> 00:07:24,000
+One more important thing the mansion here is that sequel is not case sensitive.
+
+95
+00:07:24,000 --> 00:07:31,000
+That means that no matter how you would spell create, it would still mean the same.
+
+96
+00:07:31,000 --> 00:07:35,000
+You can write it with capital letters all lowercase.
+
+97
+00:07:35,000 --> 00:07:38,000
+Technically speaking, and doesn't matter at all.
+
+98
+00:07:38,000 --> 00:07:44,000
+But still, there is a common practice to write all sequel key words with capital letters.
+
+99
+00:07:45,000 --> 00:07:49,000
+If you are ready, let's execute the query to execute all commands.
+
+100
+00:07:49,000 --> 00:07:57,000
+Since this SQL file, you have to click this lightning icon if you want to execute on the selected commands.
+
+101
+00:07:57,000 --> 00:08:03,000
+We have to select first SQL instruction, and after that, click on Lightning Icon.
+
+102
+00:08:04,000 --> 00:08:10,000
+And if you want to execute only one statement on the keyboard's cursor, you have to click this icon.
+
+103
+00:08:11,000 --> 00:08:16,000
+I execute query after it has been successfully executed.
+
+104
+00:08:16,000 --> 00:08:21,000
+I click Refresh Icon and I see that new database is created.
+
+105
+00:08:21,000 --> 00:08:28,000
+Let me select this database to make sure that all other queries will be executed against this database.
+
+106
+00:08:29,000 --> 00:08:36,000
+I am going to save each query that will review today with you in a separate file in attachments to the
+
+107
+00:08:36,000 --> 00:08:39,000
+lesson, you will be able to find all these queries.
+
+108
+00:08:40,000 --> 00:08:43,000
+Now, let's learn how we can create table.
+
+109
+00:08:44,000 --> 00:08:50,000
+I believe you already understood the general structure of great query, but still on the slide you can
+
+110
+00:08:50,000 --> 00:08:53,000
+see specifics of create table statement.
+
+111
+00:08:53,000 --> 00:08:57,000
+This query is much more complicated than create database query.
+
+112
+00:08:57,000 --> 00:09:04,000
+We can come up with some different combinations and variations that it will take more than one slides
+
+113
+00:09:04,000 --> 00:09:05,000
+to describe all of them.
+
+114
+00:09:06,000 --> 00:09:09,000
+That's why I would try to share with you.
+
+115
+00:09:09,000 --> 00:09:15,000
+The most general and high level structure of this statement mentions the most important things, in
+
+116
+00:09:15,000 --> 00:09:16,000
+my opinion.
+
+117
+00:09:16,000 --> 00:09:22,000
+In case you would like to know more details, you can always refer to the official documentation.
+
+118
+00:09:23,000 --> 00:09:31,000
+Basically, when you try to create stable followed by table name and after that parentheses, we have
+
+119
+00:09:31,000 --> 00:09:37,000
+to list all columns with their data types specifying size for each field.
+
+120
+00:09:37,000 --> 00:09:46,000
+If needed, we can specify primary key column name and if we need, we can create index by specifying
+
+121
+00:09:46,000 --> 00:09:54,000
+its style column name sorting that might be easier ascendent understanding and its visibility.
+
+122
+00:09:55,000 --> 00:10:01,000
+Just to remind you that it might be visible or not visible in case you're not familiar with indexes
+
+123
+00:10:01,000 --> 00:10:01,000
+and databases.
+
+124
+00:10:02,000 --> 00:10:08,000
+Please make sure you watched the previous lesson in this course about indexes in databases.
+
+125
+00:10:08,000 --> 00:10:16,000
+We reviewed all properties of indexes, any details on the example you can see and after you listed
+
+126
+00:10:16,000 --> 00:10:20,000
+all columns and added necessary properties to columns.
+
+127
+00:10:20,000 --> 00:10:24,000
+We can specify engine type that we want to use for this table.
+
+128
+00:10:25,000 --> 00:10:32,000
+I believe you remember that we can specify charset and collation on different levels, the specified
+
+129
+00:10:32,000 --> 00:10:35,000
+SHAZAD and collation on the table level.
+
+130
+00:10:35,000 --> 00:10:38,000
+You can put these statements at the end of the query.
+
+131
+00:10:38,000 --> 00:10:39,000
+That's it.
+
+132
+00:10:40,000 --> 00:10:43,000
+Let's execute real query against database.
+
+133
+00:10:44,000 --> 00:10:50,000
+Here, an example you can see SQL create statement that will create separate table for us was named
+
+134
+00:10:50,000 --> 00:10:52,000
+best table in this database.
+
+135
+00:10:53,000 --> 00:10:55,000
+Pay attention to a separate database.
+
+136
+00:10:55,000 --> 00:11:02,000
+Name and table name was Dot in case you selected this database in my school workbench.
+
+137
+00:11:02,000 --> 00:11:10,000
+There is no need to specify the full table name to make sure it will be created in the current database.
+
+138
+00:11:11,000 --> 00:11:16,000
+In this case, this declaration is redundant and you can remove it.
+
+139
+00:11:16,000 --> 00:11:18,000
+Result will be the same.
+
+140
+00:11:19,000 --> 00:11:22,000
+Here is a list of attributes that I want to have in my table.
+
+141
+00:11:23,000 --> 00:11:28,000
+Next to an attribute, I specify all properties related to this column.
+
+142
+00:11:29,000 --> 00:11:36,000
+It is a type and not now and all the incremented first name attribute is of type word.
+
+143
+00:11:36,000 --> 00:11:42,000
+Char was maximum lengths of forty five with no default value and so on.
+
+144
+00:11:43,000 --> 00:11:51,000
+Primary key is ID column I create a unique index was name email, unique for email column with ascending
+
+145
+00:11:51,000 --> 00:11:57,000
+order and also I specify engine charset and collation.
+
+146
+00:11:57,000 --> 00:11:58,000
+Is that clear?
+
+147
+00:11:59,000 --> 00:12:05,000
+And even in case you have any questions, you can always ask your questions in comments to the reader,
+
+148
+00:12:05,000 --> 00:12:07,000
+and I will be happy to answer.
+
+149
+00:12:08,000 --> 00:12:13,000
+Let's execute this query and we seize that query has been successfully executed.
+
+150
+00:12:13,000 --> 00:12:17,000
+After we refresh, we seize a test table is created.
+
+151
+00:12:21,000 --> 00:12:25,000
+You already saw how to create index during the creation of the table.
+
+152
+00:12:26,000 --> 00:12:31,000
+But let's imagine that we create a table and we simply forgot to create an index.
+
+153
+00:12:32,000 --> 00:12:34,000
+We still can create index afterwards.
+
+154
+00:12:35,000 --> 00:12:38,000
+Let's learn how to do this on this slide.
+
+155
+00:12:38,000 --> 00:12:42,000
+You can see structure of create in the statement you're in the creation.
+
+156
+00:12:42,000 --> 00:12:46,000
+We need to specify which type of index we would like to create.
+
+157
+00:12:46,000 --> 00:12:51,000
+The difference between these types was covered in the lesson about indexes.
+
+158
+00:12:52,000 --> 00:13:00,000
+You specify index name and on which table and column you would like to create this and this on the slide.
+
+159
+00:13:00,000 --> 00:13:07,000
+You can also notice that there might be different index options, index types, algorithm options and
+
+160
+00:13:07,000 --> 00:13:08,000
+lock options.
+
+161
+00:13:09,000 --> 00:13:12,000
+Let's grade index for our new table.
+
+162
+00:13:12,000 --> 00:13:17,000
+Just for the sake of example, let's create an index for the first name column.
+
+163
+00:13:18,000 --> 00:13:19,000
+I'm here on the screen.
+
+164
+00:13:19,000 --> 00:13:23,000
+You can see a simplified version of Create Index.
+
+165
+00:13:23,000 --> 00:13:30,000
+I specify name of my index table column in this table and index option.
+
+166
+00:13:30,000 --> 00:13:32,000
+Let me ask the this query.
+
+167
+00:13:33,000 --> 00:13:41,000
+We see the query has been executed successfully, but it is obvious that no rows were affected to make
+
+168
+00:13:41,000 --> 00:13:44,000
+sure that we really created the index when needed.
+
+169
+00:13:44,000 --> 00:13:52,000
+I open all the table and on index type I can see as an index was my name that I have just great.
+
+170
+00:13:53,000 --> 00:13:55,000
+That's how easily I can create indexes.
+
+171
+00:13:56,000 --> 00:14:02,000
+Also, index might be added as part of output table instruction, but we are going to use this later
+
+172
+00:14:02,000 --> 00:14:07,000
+in our lesson when we'll start learning of all the statement and details.
+
+173
+00:14:08,000 --> 00:14:15,000
+One of my main goal as a tutor is not just to teach you each possible combination of swearing, but
+
+174
+00:14:15,000 --> 00:14:22,000
+also I have to teach you how to understand the documentation in order you could easily proceed yourself
+
+175
+00:14:22,000 --> 00:14:23,000
+education.
+
+176
+00:14:23,000 --> 00:14:26,000
+The Gazette reviewed few queries already.
+
+177
+00:14:27,000 --> 00:14:33,000
+And for example, if you need to create view via a sequel, you don't need to open this lesson.
+
+178
+00:14:33,000 --> 00:14:39,000
+You can always open the official documentation of specific relational database management system and
+
+179
+00:14:39,000 --> 00:14:40,000
+check the details.
+
+180
+00:14:41,000 --> 00:14:46,000
+For example, now on the screen, you can see documentation page of my school.
+
+181
+00:14:47,000 --> 00:14:53,000
+From this page, you can find general construction of create, view statement and all possible options.
+
+182
+00:14:54,000 --> 00:15:00,000
+We have just reviewed similar ones, and I believe you'll really understand how to read this syntax
+
+183
+00:15:00,000 --> 00:15:01,000
+by analogy.
+
+184
+00:15:02,000 --> 00:15:08,000
+Press a pause for a minute, if needed, or just feel free to explore attachments to the lesson and
+
+185
+00:15:08,000 --> 00:15:12,000
+find this link to the official documentation that I've shared with you.
+
+186
+00:15:13,000 --> 00:15:18,000
+Additionally, if you scroll down a bit, you can also find examples of SQL queries.
+
+187
+00:15:19,000 --> 00:15:24,000
+You can create your own queries from database and your application by analogy.
+
+188
+00:15:25,000 --> 00:15:29,000
+And at the meantime, let's proceed with another examples.
+
+189
+00:15:30,000 --> 00:15:37,000
+Let's learn now such important statements as all the statements we use, all the statements when we
+
+190
+00:15:37,000 --> 00:15:44,000
+need to update the database object, no matter whether we need to update the database or table, we
+
+191
+00:15:44,000 --> 00:15:50,000
+are going to start query with all the keywords as you already know how to use the commendation.
+
+192
+00:15:50,000 --> 00:15:55,000
+I don't see a lot of reasons to go over each alter statement.
+
+193
+00:15:55,000 --> 00:15:57,000
+I mean, I will not damage you now.
+
+194
+00:15:57,000 --> 00:16:04,000
+All possible variations of all of the statements that includes and in columns and column properties
+
+195
+00:16:04,000 --> 00:16:08,000
+change enough charset and collation and lots more.
+
+196
+00:16:08,000 --> 00:16:12,000
+For the sake of the Namma, I will demo only one case was also in table.
+
+197
+00:16:12,000 --> 00:16:18,000
+In order you could understand how it works, let's adjust this table.
+
+198
+00:16:18,000 --> 00:16:26,000
+We are going to add new column after the first name and adjust first name index to change ordering in
+
+199
+00:16:26,000 --> 00:16:28,000
+there from ascending the descending.
+
+200
+00:16:29,000 --> 00:16:37,000
+I write alter table and after that I specifies a full table name, and after that I put instructions
+
+201
+00:16:37,000 --> 00:16:47,000
+related to my table of the I want to add column was name plus name was version, data type and default.
+
+202
+00:16:47,000 --> 00:16:56,000
+No value after first name column to accommodate index, I need to drop existing index first and after
+
+203
+00:16:56,000 --> 00:16:58,000
+that to add new index was descending.
+
+204
+00:16:58,000 --> 00:17:02,000
+Order Drop Command Remove Index.
+
+205
+00:17:03,000 --> 00:17:07,000
+Let me execute this query query is successfully executed.
+
+206
+00:17:08,000 --> 00:17:11,000
+Let's open table now and here is our new column.
+
+207
+00:17:12,000 --> 00:17:14,000
+We can also check our index.
+
+208
+00:17:15,000 --> 00:17:19,000
+We can see that we have to send an order in our index.
+
+209
+00:17:19,000 --> 00:17:23,000
+Basically, that's all what I wanted to share with you regarding all the query.
+
+210
+00:17:24,000 --> 00:17:29,000
+You can rename table using separate statement from data definition language.
+
+211
+00:17:29,000 --> 00:17:30,000
+It is called Renee.
+
+212
+00:17:31,000 --> 00:17:35,000
+We can easily rename our table to test DB.
+
+213
+00:17:36,000 --> 00:17:40,000
+And after refresh, we seize a table name has been changed.
+
+214
+00:17:41,000 --> 00:17:47,000
+One more interesting statement truncate we can create statements that will empty all table.
+
+215
+00:17:48,000 --> 00:17:54,000
+You to add some fake data in it first, for example, let me add just one row in this table.
+
+216
+00:17:55,000 --> 00:17:56,000
+Give me a few seconds.
+
+217
+00:18:07,000 --> 00:18:15,000
+As you see, now, we have some data in the table, and when I try to extract all the rows from table
+
+218
+00:18:15,000 --> 00:18:19,000
+one more time, I see that my role is in place.
+
+219
+00:18:20,000 --> 00:18:27,000
+If you're interested how to perform such basic operations as data insertion inside workbench, please
+
+220
+00:18:27,000 --> 00:18:30,000
+refer to lesson about my skill workbench.
+
+221
+00:18:31,000 --> 00:18:33,000
+Now we can execute the following statement.
+
+222
+00:18:34,000 --> 00:18:36,000
+TRUNCATE test to.
+
+223
+00:18:37,000 --> 00:18:39,000
+It should remove all rows in table.
+
+224
+00:18:40,000 --> 00:18:43,000
+And you can see that all rows have been removed.
+
+225
+00:18:44,000 --> 00:18:45,000
+Let's move on.
+
+226
+00:18:46,000 --> 00:18:53,000
+And the last, but not the listing for today that I'd like to show you is drop statements, we use drop
+
+227
+00:18:53,000 --> 00:18:56,000
+statement when we need to remove database object.
+
+228
+00:18:56,000 --> 00:19:02,000
+For example, if you want to remove a table or database, you have to use drop statement.
+
+229
+00:19:02,000 --> 00:19:05,000
+Let's review example of the nation of our database.
+
+230
+00:19:06,000 --> 00:19:13,000
+The database we have to execute the following query drop database and database name.
+
+231
+00:19:13,000 --> 00:19:17,000
+Everything is simple according to documentation you can add.
+
+232
+00:19:17,000 --> 00:19:22,000
+If exists, check a database only if it is present.
+
+233
+00:19:23,000 --> 00:19:24,000
+That's all for this lesson.
+
+234
+00:19:25,000 --> 00:19:27,000
+Let's recap what we have learned today.
+
+235
+00:19:28,000 --> 00:19:31,000
+We have learned a lot of different sinks in this lesson.
+
+236
+00:19:31,000 --> 00:19:33,000
+Some of them are now.
+
+237
+00:19:33,000 --> 00:19:36,000
+You know what sequel is after this lesson?
+
+238
+00:19:36,000 --> 00:19:38,000
+You know, sequels, some languages.
+
+239
+00:19:38,000 --> 00:19:47,000
+Zaire did the al DML DCL and to see out on real examples, we learned create statements.
+
+240
+00:19:48,000 --> 00:19:55,000
+Also, I explained all to rename, truncate and drop statements after this lesson, you know how to
+
+241
+00:19:55,000 --> 00:19:57,000
+build queries with mansion statements.
+
+242
+00:19:58,000 --> 00:20:00,000
+That's all for this lesson.
+
+243
+00:20:00,000 --> 00:20:02,000
+Thanks you all for your attention.
+
+244
+00:20:02,000 --> 00:20:05,000
+Have a great day and see you in the next lesson.
+

48 - SQL/002 INSERT-statement-documentation.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://dev.mysql.com/doc/refman/8.0/en/insert.html

48 - SQL/002 Query-Examples-that-were-shown-in-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/dml

48 - SQL/002 SQL DML - CRUD Operations (SELECT, INSERT, UPDATE, DELETE)_en.srt

@@ -0,0 +1,1380 @@
+1
+00:00:05,000 --> 00:00:06,000
+Hello, Tim.
+
+2
+00:00:06,000 --> 00:00:12,000
+Today we're going to learn data manipulation language will learn main statements from Male Group of
+
+3
+00:00:12,000 --> 00:00:13,000
+Sequel.
+
+4
+00:00:13,000 --> 00:00:19,000
+And will review real examples to help you understand how you can apply this knowledge on practice.
+
+5
+00:00:20,000 --> 00:00:27,000
+We'll start our lesson from understanding of select statements will spend a significant amount of power,
+
+6
+00:00:27,000 --> 00:00:34,000
+our lesson learned select statement considering that this is probably the most popular statement that
+
+7
+00:00:34,000 --> 00:00:42,000
+you are going to use it as different variations and options that I believe you should know that includes
+
+8
+00:00:42,000 --> 00:00:44,000
+order by were close.
+
+9
+00:00:44,000 --> 00:00:48,000
+Distinct search by pardon, et cetera.
+
+10
+00:00:48,000 --> 00:00:54,000
+I'm going to explain you different operators and sequels that you can use in your queries.
+
+11
+00:00:55,000 --> 00:00:59,000
+We'll review aggregate functions that are often used with select statements.
+
+12
+00:01:00,000 --> 00:01:06,000
+You're going to learn how to group result of select statement and apply condition on it.
+
+13
+00:01:06,000 --> 00:01:12,000
+And also, we're going to learn and review aussi important statements from your e-mail.
+
+14
+00:01:12,000 --> 00:01:17,000
+You'll see examples was insert, update and delete statements.
+
+15
+00:01:17,000 --> 00:01:19,000
+Let's start our lesson.
+
+16
+00:01:20,000 --> 00:01:28,000
+During your career as an engineer, you're going to hear very often such acronyms as crap it stands
+
+17
+00:01:28,000 --> 00:01:37,000
+for create, read, update, delete in computer programming crowd operations as a full basic operations
+
+18
+00:01:37,000 --> 00:01:38,000
+of persistent storage.
+
+19
+00:01:39,000 --> 00:01:48,000
+Craft is also sometimes used to describe user interface conventions that facilitate viewing, searching
+
+20
+00:01:48,000 --> 00:01:54,000
+and changing information using computer based forms and reports data manipulation.
+
+21
+00:01:54,000 --> 00:02:02,000
+Language describes syntax that will allow you to perform crud operations on the database layer, basically
+
+22
+00:02:03,000 --> 00:02:10,000
+to create, or, in other words, to insert rows in tables to read data from database or, in other
+
+23
+00:02:10,000 --> 00:02:18,000
+words, to select roles that match conditions to update throws and to delete rows that you don't need
+
+24
+00:02:18,000 --> 00:02:19,000
+anymore.
+
+25
+00:02:19,000 --> 00:02:24,000
+And the first statement that I'd like to review with you today is select statement.
+
+26
+00:02:25,000 --> 00:02:29,000
+This is a really important statement that I believe you are going to use very often.
+
+27
+00:02:29,000 --> 00:02:34,000
+That's why I would like to review different variations of the statement on the slide.
+
+28
+00:02:34,000 --> 00:02:38,000
+You can see how select statement is described in my sequel.
+
+29
+00:02:38,000 --> 00:02:39,000
+Official documentation.
+
+30
+00:02:40,000 --> 00:02:44,000
+As you can see, it contains really a lot of different variations.
+
+31
+00:02:45,000 --> 00:02:47,000
+Some of them, we are going to learn in this lesson.
+
+32
+00:02:48,000 --> 00:02:50,000
+Some of them will keep learning and other lessons.
+
+33
+00:02:51,000 --> 00:02:54,000
+Let me show you a simplified version of Select Statement.
+
+34
+00:02:55,000 --> 00:02:59,000
+On this slide, you see a simplified version of select statements.
+
+35
+00:02:59,000 --> 00:03:01,000
+Let's learn it for now.
+
+36
+00:03:01,000 --> 00:03:04,000
+And we are going to learn even more in practice.
+
+37
+00:03:05,000 --> 00:03:10,000
+You can write select, followed by asterisk from and specify table name.
+
+38
+00:03:11,000 --> 00:03:14,000
+Asterisk stands for all attributes.
+
+39
+00:03:14,000 --> 00:03:20,000
+This is like mask that is used to extract all attributes of selected tuple.
+
+40
+00:03:21,000 --> 00:03:25,000
+Next things you can see on this slide is example of search and query.
+
+41
+00:03:26,000 --> 00:03:32,000
+It is worth to say that searching on the database side is plus, rather than extracting onslaught of
+
+42
+00:03:32,000 --> 00:03:35,000
+data and sources in memory of the app.
+
+43
+00:03:36,000 --> 00:03:43,000
+That's why sometimes this query might come in handy, especially when you want to implement pagination.
+
+44
+00:03:43,000 --> 00:03:51,000
+A little bit later, we're going to talk about pagination, so to search items and database site, you
+
+45
+00:03:51,000 --> 00:03:55,000
+still use the same select statement, but you have to add order.
+
+46
+00:03:55,000 --> 00:04:01,000
+By the end of the query, you should specify column that you are going to use for searching.
+
+47
+00:04:02,000 --> 00:04:05,000
+By default, searching is in ascending order.
+
+48
+00:04:06,000 --> 00:04:12,000
+That's why usually you may need sorting order option if you are good with default sorting.
+
+49
+00:04:13,000 --> 00:04:20,000
+But if you want rows to be sorted in descending order, you have to specify this vividly.
+
+50
+00:04:20,000 --> 00:04:25,000
+You can source all the rows by two or more columns if needed.
+
+51
+00:04:26,000 --> 00:04:31,000
+Just list columns that you want to use for certain separate by comma.
+
+52
+00:04:31,000 --> 00:04:38,000
+Like in the example on the slide, you want to search all the rows by field one in descending order
+
+53
+00:04:39,000 --> 00:04:41,000
+and by field two in ascending order.
+
+54
+00:04:42,000 --> 00:04:50,000
+Besides selecting all roles with all fields, you can be more specific, for example, after select
+
+55
+00:04:50,000 --> 00:04:54,000
+keywords, you can least fields that you want to extract.
+
+56
+00:04:55,000 --> 00:04:59,000
+Also, you can put them close and specify select conditions.
+
+57
+00:05:00,000 --> 00:05:08,000
+In this case, we need to select all roles where field one has to be less than 10, and Field two has
+
+58
+00:05:08,000 --> 00:05:17,000
+to be equal to X and believe you are smart enough to understand the type of data query should match
+
+59
+00:05:17,000 --> 00:05:18,000
+was data type of the column.
+
+60
+00:05:19,000 --> 00:05:22,000
+You can use logical conjunction keywords.
+
+61
+00:05:23,000 --> 00:05:29,000
+You can use IZA and or or keywords when you use and do.
+
+62
+00:05:29,000 --> 00:05:38,000
+Conditions will be very in each Stacpoole and only zone is that much of these conditions will be returned.
+
+63
+00:05:38,000 --> 00:05:47,000
+If you use or that means that in case at least one of these conditions is Matt will return zero.
+
+64
+00:05:47,000 --> 00:05:55,000
+These are not the only logical operators a little bit later today in the lesson we are going to review
+
+65
+00:05:55,000 --> 00:05:57,000
+other operators too.
+
+66
+00:05:57,000 --> 00:06:05,000
+But I would say that most of the times you would use either and or or use every single year so far.
+
+67
+00:06:06,000 --> 00:06:12,000
+Remember that even in case you have any questions, you can always write them in the comments to this
+
+68
+00:06:12,000 --> 00:06:13,000
+video.
+
+69
+00:06:14,000 --> 00:06:20,000
+And if this small piece of theory is clear for you, that means we are going to proceed with real examples
+
+70
+00:06:20,000 --> 00:06:23,000
+and learning of you select statements.
+
+71
+00:06:24,000 --> 00:06:28,000
+Now let's execute these statements against data in database.
+
+72
+00:06:29,000 --> 00:06:34,000
+And as usual, I'm going to save all queries that will be used in this lesson.
+
+73
+00:06:34,000 --> 00:06:38,000
+And you will find them in attachments to the lesson.
+
+74
+00:06:38,000 --> 00:06:45,000
+Having the same queries will allow you to run the same queries on your own computer to understand as
+
+75
+00:06:45,000 --> 00:06:46,000
+a topic better.
+
+76
+00:06:47,000 --> 00:06:52,000
+Before we start execute queries, make sure that your previous lessons.
+
+77
+00:06:52,000 --> 00:06:56,000
+You also created user, themore the same as I did.
+
+78
+00:06:56,000 --> 00:07:00,000
+Also pay attention that we already pasted some information here.
+
+79
+00:07:01,000 --> 00:07:09,000
+I just changed the names and emails here to make it look more realistic because to be able to see how
+
+80
+00:07:09,000 --> 00:07:13,000
+select statements work, you have to have some data first.
+
+81
+00:07:13,000 --> 00:07:20,000
+So as you can see, the simplest query is to select all couples from user table, and it looks like
+
+82
+00:07:20,000 --> 00:07:23,000
+this nice and special and great.
+
+83
+00:07:24,000 --> 00:07:32,000
+If you want to extract on the specific fields, you should list them instead of asterisk, like I did
+
+84
+00:07:32,000 --> 00:07:34,000
+here in this particular example.
+
+85
+00:07:34,000 --> 00:07:38,000
+I want to extract on the first name and last name.
+
+86
+00:07:38,000 --> 00:07:43,000
+Let's sort now fills my last name in descending order.
+
+87
+00:07:43,000 --> 00:07:47,000
+And after that, my first name in descending order.
+
+88
+00:07:48,000 --> 00:07:52,000
+That is needed because we already have a few rows with the same last name.
+
+89
+00:07:53,000 --> 00:07:57,000
+Thus, searching only by last name won't be enough.
+
+90
+00:07:58,000 --> 00:08:02,000
+And we have to come up with additional rule for sorting.
+
+91
+00:08:02,000 --> 00:08:08,000
+I add order by keywords and specify columns that I want to use for sorting.
+
+92
+00:08:09,000 --> 00:08:10,000
+Let's execute this query.
+
+93
+00:08:11,000 --> 00:08:18,000
+Now, let's add condition I'd like to extract all rows where a last name is equal to Ivanov.
+
+94
+00:08:19,000 --> 00:08:22,000
+I write very close and specify condition.
+
+95
+00:08:23,000 --> 00:08:29,000
+And after we executed queries, we received only rows that meets our condition.
+
+96
+00:08:29,000 --> 00:08:34,000
+Regarding operators in my school, you can use different operators.
+
+97
+00:08:35,000 --> 00:08:42,000
+As I said, let's discuss operators as a separate topic and little bit later today, but ensured talking
+
+98
+00:08:42,000 --> 00:08:44,000
+about comparative operators.
+
+99
+00:08:44,000 --> 00:08:53,000
+NASA's special you can use more or less more or equal to less or equal to not equal to operators here
+
+100
+00:08:53,000 --> 00:08:53,000
+in condition.
+
+101
+00:08:54,000 --> 00:09:02,000
+One more important scene to show you is this certain keywords, for example, you need to extract all
+
+102
+00:09:02,000 --> 00:09:07,000
+different last names or names from the table without any duplicates.
+
+103
+00:09:07,000 --> 00:09:12,000
+You can use distinct keywords in the attribute to receive all the different values.
+
+104
+00:09:13,000 --> 00:09:19,000
+Like in this example, when we executed the query, we don't receive any duplicated last names.
+
+105
+00:09:19,000 --> 00:09:20,000
+Does it make sense?
+
+106
+00:09:21,000 --> 00:09:28,000
+Now, let's imagine that you forgot what you are looking for and you don't remember the search parameter.
+
+107
+00:09:29,000 --> 00:09:33,000
+But you remember that last name of the user you started from if.
+
+108
+00:09:34,000 --> 00:09:36,000
+How to find what you need.
+
+109
+00:09:36,000 --> 00:09:40,000
+You can search by specified pattern was like.
+
+110
+00:09:40,000 --> 00:09:41,000
+Operator.
+
+111
+00:09:41,000 --> 00:09:48,000
+The operator is used in a where close to search for a specified partner in the column.
+
+112
+00:09:49,000 --> 00:09:55,000
+There are two wild cards often used in conjunction with like operator Z.
+
+113
+00:09:55,000 --> 00:09:59,000
+Person Sign represents zero one or multiple characters.
+
+114
+00:09:59,000 --> 00:10:08,000
+The underscore sign represents one single character in our specific case one we want to find all rows
+
+115
+00:10:08,000 --> 00:10:14,000
+where our last name is started was safe and we don't know the full last name.
+
+116
+00:10:14,000 --> 00:10:16,000
+We need to use person sign.
+
+117
+00:10:17,000 --> 00:10:25,000
+Look at this query by this and telling us that after if there might be a different number of characters,
+
+118
+00:10:25,000 --> 00:10:28,000
+let's execute this first query.
+
+119
+00:10:28,000 --> 00:10:34,000
+And you can see that I have to tap those returns in as a query.
+
+120
+00:10:34,000 --> 00:10:39,000
+I am saying that zero is one character that is followed by me.
+
+121
+00:10:39,000 --> 00:10:45,000
+And after that, we have a different amount of characters, and I don't know how much.
+
+122
+00:10:45,000 --> 00:10:48,000
+Exactly opposite is it clear?
+
+123
+00:10:49,000 --> 00:10:56,000
+That's not what education nation is and what we need to know to support pagination on the database level,
+
+124
+00:10:57,000 --> 00:11:05,000
+pagination is a matter of divided content into discrete pages, thus presenting content in a limited
+
+125
+00:11:06,000 --> 00:11:07,000
+and digestible manner.
+
+126
+00:11:08,000 --> 00:11:16,000
+We will search result page is a typical example of such a search if you downloaded applications that
+
+127
+00:11:16,000 --> 00:11:19,000
+I created for my students, for mobile phones.
+
+128
+00:11:19,000 --> 00:11:20,000
+Learn it.
+
+129
+00:11:20,000 --> 00:11:24,000
+You can find the example of pagination in the history.
+
+130
+00:11:25,000 --> 00:11:33,000
+If you have a lot of tests and certifications passed and you open history inside the app to explore
+
+131
+00:11:33,000 --> 00:11:41,000
+your previous results, you can scroll test results, but not all test results extracted from the database
+
+132
+00:11:41,000 --> 00:11:42,000
+at once.
+
+133
+00:11:43,000 --> 00:11:47,000
+They are loaded in chunks after you scrolled to the lowest record.
+
+134
+00:11:48,000 --> 00:11:51,000
+I extracted records from a database by small chunks.
+
+135
+00:11:52,000 --> 00:11:59,000
+Instead of extracting all of the latest records at once during the stand, imagine that you have 100
+
+136
+00:11:59,000 --> 00:12:05,000
+or even 1000 test results, but you need to check on the few last ones.
+
+137
+00:12:05,000 --> 00:12:13,000
+In this case, is any sense to extract all rows and pass them from the server into the mobile app.
+
+138
+00:12:14,000 --> 00:12:15,000
+Definitely not.
+
+139
+00:12:15,000 --> 00:12:23,000
+That's why you're in the design of our app before we see that we need pagination support here and to
+
+140
+00:12:23,000 --> 00:12:26,000
+be even more specific in mobile apps.
+
+141
+00:12:26,000 --> 00:12:33,000
+This is called Infinite's crawl, and this allows you to scroll content down without any interruption.
+
+142
+00:12:34,000 --> 00:12:40,000
+Infinite scrolling is a functionality allowing users to scroll down a massive amount of information,
+
+143
+00:12:41,000 --> 00:12:48,000
+presenting it in easy to consume chunks and data is uploaded as you reached the lowest records on the
+
+144
+00:12:48,000 --> 00:12:49,000
+screen.
+
+145
+00:12:49,000 --> 00:12:55,000
+I'm sure you're faced with such design while using other apps in database.
+
+146
+00:12:55,000 --> 00:12:59,000
+We can support pagination by extracting specified range of records.
+
+147
+00:12:59,000 --> 00:13:06,000
+With the help of limit operator, the cycle limit close restricts how many rows are returned from a
+
+148
+00:13:06,000 --> 00:13:07,000
+query.
+
+149
+00:13:07,000 --> 00:13:14,000
+The syntax for the limit close represents how many requests you want to retrieve and starting from which
+
+150
+00:13:14,000 --> 00:13:22,000
+record, for example, you can use is a limit close to retrieves a top five users by number of coins.
+
+151
+00:13:23,000 --> 00:13:30,000
+Or you could extract the user starting from the six position to tance sorted by number of coins.
+
+152
+00:13:31,000 --> 00:13:36,000
+Zeleny The class is only compatible with the sequel select statement.
+
+153
+00:13:36,000 --> 00:13:40,000
+You can use a limit class in SQL Update statement.
+
+154
+00:13:40,000 --> 00:13:44,000
+For instance, your limit number must be positive.
+
+155
+00:13:45,000 --> 00:13:48,000
+Say you want to retrieve records from the bottom of the list.
+
+156
+00:13:49,000 --> 00:13:54,000
+You should use a sequel or buy statement to order them in descending order.
+
+157
+00:13:55,000 --> 00:13:57,000
+Then you should use any misstatement.
+
+158
+00:13:58,000 --> 00:14:01,000
+Let's learn how to work with limited statement on practice.
+
+159
+00:14:02,000 --> 00:14:03,000
+We have three requests here.
+
+160
+00:14:04,000 --> 00:14:09,000
+Let me extract two users sorted by email in ascending order.
+
+161
+00:14:09,000 --> 00:14:13,000
+I write Select all from user order by email.
+
+162
+00:14:14,000 --> 00:14:22,000
+Limit to the last four limit two means that it would return me to records only.
+
+163
+00:14:22,000 --> 00:14:27,000
+Let's execute this query, and you can see that where was these?
+
+164
+00:14:27,000 --> 00:14:30,000
+Three and four have been returned.
+
+165
+00:14:31,000 --> 00:14:35,000
+But as we have already discussed, we can specify offset.
+
+166
+00:14:35,000 --> 00:14:37,000
+We add additional parameter.
+
+167
+00:14:37,000 --> 00:14:46,000
+In the second example, offset is one, so we are skipping the first one returned and will return to
+
+168
+00:14:46,000 --> 00:14:48,000
+records after the first one.
+
+169
+00:14:48,000 --> 00:14:49,000
+Does it make sense?
+
+170
+00:14:50,000 --> 00:14:55,000
+So we return to records after keeping the first records?
+
+171
+00:14:55,000 --> 00:14:59,000
+Basically from the second position of our ordering.
+
+172
+00:15:00,000 --> 00:15:07,000
+And now when we execute this query, we have records with I.D. four and one return.
+
+173
+00:15:07,000 --> 00:15:15,000
+Is it clear for you why this is happening and when you implement queries for your app, you can build
+
+174
+00:15:15,000 --> 00:15:16,000
+them accordingly.
+
+175
+00:15:16,000 --> 00:15:23,000
+For example, you can post as a server parameters of pages that you want to retrieve and the number
+
+176
+00:15:23,000 --> 00:15:26,000
+of trackers and paste them into the query.
+
+177
+00:15:27,000 --> 00:15:29,000
+Anyways, this is not a topic of this lesson.
+
+178
+00:15:29,000 --> 00:15:34,000
+It is just a hint we'll learn how to implement this one.
+
+179
+00:15:34,000 --> 00:15:38,000
+We'll start learning of that application development as of now.
+
+180
+00:15:39,000 --> 00:15:43,000
+I want you to know and remember how to work with that statement.
+
+181
+00:15:44,000 --> 00:15:51,000
+The next thing that I'd like to amuse you is Quarians, and no attributes, just a smile or see them
+
+182
+00:15:51,000 --> 00:15:59,000
+then, but still very important, and a lot of my students do the same mistake when they just start
+
+183
+00:15:59,000 --> 00:16:00,000
+to use in school.
+
+184
+00:16:00,000 --> 00:16:08,000
+If you want to select couples that have no value in some of the attributes, you can just use equal
+
+185
+00:16:08,000 --> 00:16:09,000
+operator.
+
+186
+00:16:10,000 --> 00:16:16,000
+Let me show you if you want to select users is that's no value in the f k user all field.
+
+187
+00:16:17,000 --> 00:16:24,000
+You can't just use equal operator because it won't give you results that you expect.
+
+188
+00:16:24,000 --> 00:16:31,000
+Instead, you have to use another keyword you have to use is now or is not now.
+
+189
+00:16:31,000 --> 00:16:34,000
+This is a specific that you should be aware of.
+
+190
+00:16:35,000 --> 00:16:37,000
+So please don't forget about this.
+
+191
+00:16:38,000 --> 00:16:44,000
+We already removed a few examples, and I believe you understand how to work with select statements,
+
+192
+00:16:44,000 --> 00:16:49,000
+but still and those are things that we need to learn is different operators.
+
+193
+00:16:49,000 --> 00:16:53,000
+Definitely, there is no sense to hold them off.
+
+194
+00:16:53,000 --> 00:16:58,000
+Select statements on real data was each possible operator instead.
+
+195
+00:16:58,000 --> 00:17:02,000
+Problem is, there is a sense to learn different operators now.
+
+196
+00:17:02,000 --> 00:17:06,000
+I will also provide you with examples of how to apply different.
+
+197
+00:17:06,000 --> 00:17:12,000
+Operator Let's start from the first group of operators in sequel arithmetic operators.
+
+198
+00:17:13,000 --> 00:17:20,000
+Basically, there is nothing special and no signs that you didn't learn in elementary school.
+
+199
+00:17:20,000 --> 00:17:24,000
+The only exclusion is modular operator problem.
+
+200
+00:17:24,000 --> 00:17:30,000
+But if you are familiar with one of the most popular programming languages, you already knows that
+
+201
+00:17:30,000 --> 00:17:35,000
+usually person sign is used for operations to extract reminder after division.
+
+202
+00:17:36,000 --> 00:17:40,000
+If you need a few more seconds to review examples, please.
+
+203
+00:17:40,000 --> 00:17:41,000
+Grasset boss.
+
+204
+00:17:42,000 --> 00:17:43,000
+Let's continue.
+
+205
+00:17:43,000 --> 00:17:49,000
+Well, that was a group of operators that we are going to review its comparison operators.
+
+206
+00:17:49,000 --> 00:17:57,000
+Most of them are also familiar to you, probably not equal to operator may look like and you one for
+
+207
+00:17:57,000 --> 00:17:58,000
+some students.
+
+208
+00:17:59,000 --> 00:18:07,000
+Basically, the general rule is not equal to operator is written like this, but also in some relational
+
+209
+00:18:07,000 --> 00:18:08,000
+database management systems.
+
+210
+00:18:08,000 --> 00:18:15,000
+It is also possible to use another syntax of note equal to operator that is more similar to one that
+
+211
+00:18:15,000 --> 00:18:17,000
+we use in programming languages.
+
+212
+00:18:18,000 --> 00:18:25,000
+And on this slide, you can find logical operators will read your review to such logical operators as
+
+213
+00:18:25,000 --> 00:18:27,000
+and or lie.
+
+214
+00:18:28,000 --> 00:18:38,000
+But as you can see, some of them look through the table on this slide, grasp if needed, and ask questions
+
+215
+00:18:38,000 --> 00:18:42,000
+in comments to the video in case someone is still not clear here.
+
+216
+00:18:43,000 --> 00:18:50,000
+Now, let's learn aggregate functions again, then we'll use them with select statements.
+
+217
+00:18:50,000 --> 00:18:57,000
+That's why I believe it is better to use them in conjunction with select statements and aggregate function,
+
+218
+00:18:57,000 --> 00:19:06,000
+performs a calculation on a set of values and returns a single value except for count aggregate functions.
+
+219
+00:19:06,000 --> 00:19:08,000
+Ignore null values.
+
+220
+00:19:08,000 --> 00:19:15,000
+Aggregate functions are often used with the group by close of the select statement, and here in the
+
+221
+00:19:15,000 --> 00:19:22,000
+slide, you can see product table examples that I'm going to use for the explanation of the following
+
+222
+00:19:22,000 --> 00:19:23,000
+aggregate functions.
+
+223
+00:19:24,000 --> 00:19:26,000
+Let's start from the learned man and the.
+
+224
+00:19:27,000 --> 00:19:32,000
+Based on the name of these attribute functions, I believe it is easy to understand.
+
+225
+00:19:32,000 --> 00:19:39,000
+The first one returns minimal value in the column, and the second one returns the maximum value in
+
+226
+00:19:39,000 --> 00:19:39,000
+the column.
+
+227
+00:19:40,000 --> 00:19:45,000
+And on the slide, you can see example of queries executed against stable waste products.
+
+228
+00:19:46,000 --> 00:19:49,000
+We extract max and mean price.
+
+229
+00:19:50,000 --> 00:19:52,000
+The next aggregate function is count.
+
+230
+00:19:53,000 --> 00:19:59,000
+The count function returns a number of roles that matches a specified material.
+
+231
+00:19:59,000 --> 00:20:02,000
+You can also find query example on the slide.
+
+232
+00:20:03,000 --> 00:20:07,000
+The average function returns the average value of a number of column.
+
+233
+00:20:08,000 --> 00:20:12,000
+The sum function returns is a total sum of a number.
+
+234
+00:20:12,000 --> 00:20:14,000
+A column is everything clear.
+
+235
+00:20:15,000 --> 00:20:20,000
+Let's learn now group by keywords that are often used together with aggregate functions.
+
+236
+00:20:21,000 --> 00:20:28,000
+Zeiger by statement groups rows that have the same values in the summary rows, it is often used with
+
+237
+00:20:28,000 --> 00:20:29,000
+aggregate functions.
+
+238
+00:20:30,000 --> 00:20:35,000
+The group by statement groups rows that have the same values in the summary rose.
+
+239
+00:20:35,000 --> 00:20:43,000
+It is often used with aggregate functions like count marks mean some average subgroups, the results
+
+240
+00:20:43,000 --> 00:20:45,000
+said by one or more columns.
+
+241
+00:20:45,000 --> 00:20:47,000
+Let's reverse this on real demo.
+
+242
+00:20:48,000 --> 00:20:52,000
+We are going them a group by statement, an example of user table.
+
+243
+00:20:53,000 --> 00:20:57,000
+Let's find the most used a last name among our users.
+
+244
+00:20:58,000 --> 00:21:05,000
+We know that last name in our app is not unique and we want to understand how much users used the same
+
+245
+00:21:05,000 --> 00:21:06,000
+last name.
+
+246
+00:21:06,000 --> 00:21:13,000
+I want select total count of all rows and displays this count as a mount attribute.
+
+247
+00:21:13,000 --> 00:21:20,000
+And also, I want to extract the last name from user table and group results by a last name.
+
+248
+00:21:20,000 --> 00:21:22,000
+That's executed this query.
+
+249
+00:21:22,000 --> 00:21:26,000
+You can see that we have two people with even our last name.
+
+250
+00:21:26,000 --> 00:21:29,000
+And one user with Komarov last name.
+
+251
+00:21:29,000 --> 00:21:30,000
+And then the results.
+
+252
+00:21:30,000 --> 00:21:33,000
+That count has been returned as a mound column.
+
+253
+00:21:34,000 --> 00:21:41,000
+When I wrote this query, I used this error automatically because when you use aggregate functions,
+
+254
+00:21:41,000 --> 00:21:45,000
+you also ones that column would have meaningful name.
+
+255
+00:21:46,000 --> 00:21:47,000
+The syntax is simple.
+
+256
+00:21:47,000 --> 00:21:53,000
+You use ASCII words and specifies a desert attribute name, sequel aliases.
+
+257
+00:21:53,000 --> 00:21:58,000
+I used to give a table or column in the table at temporary name.
+
+258
+00:21:58,000 --> 00:22:05,000
+Aliases are often used to make column names more readable, and A. only exists for the duration of that
+
+259
+00:22:05,000 --> 00:22:11,000
+query and A. is created was SE keywords in my sequel.
+
+260
+00:22:11,000 --> 00:22:16,000
+I usually omit ASCII word and use else straight away.
+
+261
+00:22:17,000 --> 00:22:23,000
+We grouped our result by last name and managed to receive a result like this hobs.
+
+262
+00:22:23,000 --> 00:22:24,000
+This is clear now.
+
+263
+00:22:25,000 --> 00:22:33,000
+Another interesting saying that when you use group by keywords, you can apply condition to groups.
+
+264
+00:22:33,000 --> 00:22:39,000
+To do this, you have to use havant keywords in very, very simplified words.
+
+265
+00:22:39,000 --> 00:22:47,000
+Heaven is the same as where in regular select statements, the difference is that you can't apply where
+
+266
+00:22:47,000 --> 00:22:55,000
+after group by statement, because where is applied for each sample while reviewing each records, whereas
+
+267
+00:22:55,000 --> 00:22:58,000
+haven't may be applied to the group of tables.
+
+268
+00:22:58,000 --> 00:23:06,000
+Once we iterated over records in table workflows introduces a condition on individual rows, having
+
+269
+00:23:06,000 --> 00:23:09,000
+close introduces a condition on aggregations.
+
+270
+00:23:10,000 --> 00:23:13,000
+Does it make sense from human language?
+
+271
+00:23:13,000 --> 00:23:15,000
+We have few more important statements to learn.
+
+272
+00:23:16,000 --> 00:23:18,000
+Let's learn Insert statement.
+
+273
+00:23:18,000 --> 00:23:23,000
+Basically, this statement is used to insert new records in the table.
+
+274
+00:23:23,000 --> 00:23:32,000
+The general structure of insert statement looks like this insert into table name lists of columns where
+
+275
+00:23:32,000 --> 00:23:33,000
+you want to insert values.
+
+276
+00:23:34,000 --> 00:23:38,000
+After that, gross values, keyword and list of values.
+
+277
+00:23:39,000 --> 00:23:45,000
+This is the most common syntax of insert statement, but definitely is a resource a way to make simple
+
+278
+00:23:45,000 --> 00:23:47,000
+things more complex.
+
+279
+00:23:47,000 --> 00:23:48,000
+Just joking.
+
+280
+00:23:49,000 --> 00:23:55,000
+But indeed, there might be different variations of insert statements in attachments to the media.
+
+281
+00:23:55,000 --> 00:24:00,000
+You will find Link to the official documentation about insert statement in my sequel.
+
+282
+00:24:01,000 --> 00:24:07,000
+Xanax thinks that you have to remember about insert statements inserts, but suffice to table where
+
+283
+00:24:07,000 --> 00:24:11,000
+data will be inserted into we can omit column.
+
+284
+00:24:12,000 --> 00:24:19,000
+If a column is amended, each value must be provided if you include in columns that can be listed in
+
+285
+00:24:19,000 --> 00:24:25,000
+any order value specifies the data that you want to insert into the table.
+
+286
+00:24:26,000 --> 00:24:30,000
+Value is required in certain and I'm just throwing into a word.
+
+287
+00:24:30,000 --> 00:24:34,000
+Char Ortex column inserts a single space.
+
+288
+00:24:35,000 --> 00:24:43,000
+All trading spaces are removed from data inserted into large columns, except in strings that contain
+
+289
+00:24:43,000 --> 00:24:44,000
+only spaces.
+
+290
+00:24:44,000 --> 00:24:47,000
+This strings are truncated to a single space.
+
+291
+00:24:49,000 --> 00:24:57,000
+If an insert statement violates a constraint, default or rule, or if it is wrong data type, the statement
+
+292
+00:24:57,000 --> 00:25:01,000
+fails and sequels, server displays and error message.
+
+293
+00:25:02,000 --> 00:25:09,000
+Let's insert a few rows in our user table on the screen, you can see example often search query.
+
+294
+00:25:09,000 --> 00:25:16,000
+We want to insert the records, but tensions at one record has EFCC use a roll value specified.
+
+295
+00:25:17,000 --> 00:25:24,000
+And another record doesn't have the number of values should margins the number of columns we listed.
+
+296
+00:25:25,000 --> 00:25:32,000
+So let's execute the query insert statement or iTunes has a number of how many rows have been impacted.
+
+297
+00:25:32,000 --> 00:25:37,000
+After execution of this query, we impacted two rows in total.
+
+298
+00:25:37,000 --> 00:25:44,000
+Now we can select all rows in our user table and make sure that we inserted two records.
+
+299
+00:25:45,000 --> 00:25:46,000
+Is it clear?
+
+300
+00:25:47,000 --> 00:25:49,000
+If yes, then let's proceed.
+
+301
+00:25:49,000 --> 00:25:54,000
+The update statement is used to modify the existing records.
+
+302
+00:25:54,000 --> 00:25:56,000
+In the table is a general query.
+
+303
+00:25:56,000 --> 00:25:58,000
+Structure looks like this.
+
+304
+00:25:58,000 --> 00:26:00,000
+You start with update keywords.
+
+305
+00:26:01,000 --> 00:26:08,000
+After that specified table name after set keywords, we need to list pairs of column name and related
+
+306
+00:26:08,000 --> 00:26:09,000
+value.
+
+307
+00:26:09,000 --> 00:26:10,000
+Separate was comma.
+
+308
+00:26:11,000 --> 00:26:17,000
+Optionally, we can specify where a close to select rules that we want to accommodate and we can apply
+
+309
+00:26:17,000 --> 00:26:18,000
+limit.
+
+310
+00:26:19,000 --> 00:26:27,000
+The where clause, if given, specifies the conditions, is that identify which rose to update with
+
+311
+00:26:27,000 --> 00:26:28,000
+nowhere close.
+
+312
+00:26:28,000 --> 00:26:33,000
+All the rules are updated if the order by clause is specified.
+
+313
+00:26:34,000 --> 00:26:42,000
+Zero's updated in the order that a specified the limit clause places a limit on the number of rules
+
+314
+00:26:42,000 --> 00:26:43,000
+that can be updated.
+
+315
+00:26:44,000 --> 00:26:50,000
+In our example, we decided to change email for our user and assign new role for him.
+
+316
+00:26:51,000 --> 00:26:58,000
+An example you can see that I assign new value to email attribute and to f k user role attribute.
+
+317
+00:26:59,000 --> 00:27:05,000
+I use very close to update on the one row I have unique identifier in this table.
+
+318
+00:27:05,000 --> 00:27:08,000
+That's why, in workflows, I use ID.
+
+319
+00:27:09,000 --> 00:27:17,000
+Let me execute this squaring I'mnot statement also returns a number of updated throws with successfully
+
+320
+00:27:17,000 --> 00:27:18,000
+updated one rule.
+
+321
+00:27:18,000 --> 00:27:23,000
+We can check our table to make sure that email and foreign key value is changed.
+
+322
+00:27:24,000 --> 00:27:27,000
+If everything is clear, then let's move on.
+
+323
+00:27:28,000 --> 00:27:34,000
+And the last, but not least for today, the lead statement, the statement is used to delete existing
+
+324
+00:27:34,000 --> 00:27:35,000
+records in the table.
+
+325
+00:27:36,000 --> 00:27:43,000
+One important thing to mention here is that in case you would admit where close, you would remove all
+
+326
+00:27:43,000 --> 00:27:45,000
+records from the table.
+
+327
+00:27:45,000 --> 00:27:48,000
+So be very attentive with this query.
+
+328
+00:27:49,000 --> 00:27:54,000
+According to documentation, you can also use or them by and limit the keywords.
+
+329
+00:27:55,000 --> 00:27:58,000
+In that example, we decided to remove one row.
+
+330
+00:27:58,000 --> 00:28:04,000
+Here is how it look like I specified three of the role that I want to remove.
+
+331
+00:28:05,000 --> 00:28:06,000
+Let's execute this query.
+
+332
+00:28:07,000 --> 00:28:13,000
+And you can see in logs that the lead statement also returns number of rows that were impacted with
+
+333
+00:28:13,000 --> 00:28:13,000
+this query.
+
+334
+00:28:14,000 --> 00:28:17,000
+That's all I wanted to share with you in this lesson.
+
+335
+00:28:17,000 --> 00:28:19,000
+Let's recap what we have learned today.
+
+336
+00:28:20,000 --> 00:28:26,000
+In this lesson, we learned select statements, I showed you select statements with different options,
+
+337
+00:28:27,000 --> 00:28:35,000
+including selecting Rose is ordering wear clothes, distinct selection search by pardon Lehman's a number
+
+338
+00:28:35,000 --> 00:28:39,000
+of rose to be returned grouping and the blind condition on groups.
+
+339
+00:28:40,000 --> 00:28:43,000
+You learned different skill operators.
+
+340
+00:28:44,000 --> 00:28:48,000
+Now you know what aggregate functions are and how to work with them.
+
+341
+00:28:48,000 --> 00:28:52,000
+I showed you how to work with others in school.
+
+342
+00:28:52,000 --> 00:28:57,000
+And also, we discussed insert, update and delete statements.
+
+343
+00:28:58,000 --> 00:28:59,000
+That's all for this lesson.
+
+344
+00:29:00,000 --> 00:29:02,000
+Thanks a lot for your attention.
+
+345
+00:29:02,000 --> 00:29:05,000
+Have a great day and see you in the next lesson.
+

48 - SQL/003 JOIN Queries, UNION & Subqueries_en.srt

@@ -0,0 +1,732 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:12,000
+In this lesson, we continue to learn sequel and will focus on such important group of queries as joint
+
+3
+00:00:12,000 --> 00:00:13,000
+queries.
+
+4
+00:00:13,000 --> 00:00:19,000
+Considering the fact we are dealing with relational databases very often we have to create joint queries
+
+5
+00:00:19,000 --> 00:00:20,000
+to multiple tables.
+
+6
+00:00:21,000 --> 00:00:26,000
+And also, we are going to review a few more SQL statements that I didn't cover in previous lesson plans
+
+7
+00:00:26,000 --> 00:00:27,000
+that are too small.
+
+8
+00:00:27,000 --> 00:00:33,000
+For a separate lesson in the lesson, we'll put our focus on Jones sequel statements.
+
+9
+00:00:33,000 --> 00:00:42,000
+We're going to review different types of June queries that includes in the left right cross and full
+
+10
+00:00:42,000 --> 00:00:43,000
+order giants.
+
+11
+00:00:43,000 --> 00:00:47,000
+I also prepare examples for each case to review Is you?
+
+12
+00:00:47,000 --> 00:00:53,000
+You will be able to find all examples that will review each lesson in attachments to the veto.
+
+13
+00:00:54,000 --> 00:01:00,000
+Also, we are going to learn union keyword and understand how it works and that sense of the lesson.
+
+14
+00:01:00,000 --> 00:01:04,000
+I will teach you how to construct queries with sub queries.
+
+15
+00:01:05,000 --> 00:01:06,000
+Let's start our lesson.
+
+16
+00:01:07,000 --> 00:01:12,000
+I believe that you already understood that in relational databases, we split data between different
+
+17
+00:01:12,000 --> 00:01:16,000
+tables and apply normalization with data redundancy.
+
+18
+00:01:17,000 --> 00:01:25,000
+This means that to extract data that you need, sometimes you need to execute so-called joint queries
+
+19
+00:01:25,000 --> 00:01:33,000
+against not one, but multiple tables in step joint query commands, columns from one or more tables
+
+20
+00:01:33,000 --> 00:01:42,000
+into a new table and see standard sequels insofar as five types of joy in the left order, right order,
+
+21
+00:01:42,000 --> 00:01:44,000
+food order and cross.
+
+22
+00:01:45,000 --> 00:01:50,000
+Let's learn how these joints look in theory, and after that, we review practice examples.
+
+23
+00:01:51,000 --> 00:01:58,000
+Further examples will be shown considering these two tables user and role that actions at user table
+
+24
+00:01:58,000 --> 00:02:06,000
+contains foreign key to role table and also Xerri users without rules and also the roles that are not
+
+25
+00:02:06,000 --> 00:02:08,000
+assigned to any user.
+
+26
+00:02:09,000 --> 00:02:14,000
+The same tables I have in my school, we created zones during the previous lessons.
+
+27
+00:02:15,000 --> 00:02:19,000
+If you want to repeat queries after me, make sure you have the same tables.
+
+28
+00:02:20,000 --> 00:02:28,000
+The best visualization of Junqueras is these two circles your circles represent the set of records that
+
+29
+00:02:28,000 --> 00:02:29,000
+exist in two tables.
+
+30
+00:02:30,000 --> 00:02:36,000
+Basically, you can see that one table is on the left and another table is on the right.
+
+31
+00:02:36,000 --> 00:02:44,000
+That tangent that these two circles have intersection zigzag in the records is it can be mapped between
+
+32
+00:02:44,000 --> 00:02:45,000
+each other.
+
+33
+00:02:45,000 --> 00:02:54,000
+In simple words, the area inside these two circles is called in a joint area that includes space without
+
+34
+00:02:54,000 --> 00:02:55,000
+intersection.
+
+35
+00:02:55,000 --> 00:02:58,000
+It's called the left and right or the John.
+
+36
+00:02:59,000 --> 00:03:06,000
+Anyway, we're going to review each of you and type on real examples and one by one, and let's start
+
+37
+00:03:06,000 --> 00:03:07,000
+from Injune.
+
+38
+00:03:07,000 --> 00:03:14,000
+You can imagine it as an intersection between two tables and enjoying requires each row in the two joints
+
+39
+00:03:14,000 --> 00:03:17,000
+tables to have matching column values.
+
+40
+00:03:18,000 --> 00:03:25,000
+This is exactly the moment when we'll use our foreign keys to establish connections between tables in
+
+41
+00:03:25,000 --> 00:03:27,000
+a joint creates and result table.
+
+42
+00:03:27,000 --> 00:03:35,000
+By combining column values of two tables based upon the joint predicate, imagine that we have two tables.
+
+43
+00:03:35,000 --> 00:03:37,000
+Z are A and B.
+
+44
+00:03:37,000 --> 00:03:47,000
+Table Zucchero compares each row of a with each row of D to find all pairs of rows that satisfy the
+
+45
+00:03:47,000 --> 00:03:49,000
+joint pretty good ones.
+
+46
+00:03:49,000 --> 00:03:52,000
+A joint project is satisfied by matching non low values.
+
+47
+00:03:52,000 --> 00:03:59,000
+Common values for each pair of rows of A and B are combined into result.
+
+48
+00:03:59,000 --> 00:04:08,000
+Row six specifies two different syntactical ways to express joints z explicit joint notation and same
+
+49
+00:04:08,000 --> 00:04:14,000
+place adjourn notation simply to join notation is no longer considered the best practice.
+
+50
+00:04:14,000 --> 00:04:17,000
+Also, database system still supported.
+
+51
+00:04:17,000 --> 00:04:26,000
+The explicit annotation uses a joint keyword optionally preceded by a keyword to specify the table to
+
+52
+00:04:26,000 --> 00:04:30,000
+join and the only keyword to specify the precursor for the joint.
+
+53
+00:04:31,000 --> 00:04:34,000
+Today, we're going to review a different query examples.
+
+54
+00:04:35,000 --> 00:04:36,000
+I save all of them.
+
+55
+00:04:36,000 --> 00:04:40,000
+You will be able to find those in attachments to this lesson.
+
+56
+00:04:41,000 --> 00:04:45,000
+Let me show you a demo of in our John Kerry just to remind you.
+
+57
+00:04:45,000 --> 00:04:48,000
+Here is how our user table looks like.
+
+58
+00:04:48,000 --> 00:04:50,000
+Not all users have role.
+
+59
+00:04:51,000 --> 00:04:53,000
+And here's how our old table looks like.
+
+60
+00:04:54,000 --> 00:04:59,000
+Zero rules that are not a science None of the users is that clear.
+
+61
+00:05:00,000 --> 00:05:06,000
+Now let's select last name and role name of all users with their roles.
+
+62
+00:05:06,000 --> 00:05:11,000
+We will not take into account users without rows and rows without users.
+
+63
+00:05:12,000 --> 00:05:16,000
+I write select fields that they need and their attention.
+
+64
+00:05:16,000 --> 00:05:21,000
+I use tables on us to specify which fields from each table I want to extract.
+
+65
+00:05:22,000 --> 00:05:26,000
+After that, I write from users table and pay attention.
+
+66
+00:05:26,000 --> 00:05:34,000
+I specify August here you is just a character that seems for me to be good as an alias for this table.
+
+67
+00:05:35,000 --> 00:05:42,000
+Basically, you last name in our query is a reference to the last name field in user table.
+
+68
+00:05:43,000 --> 00:05:43,000
+Is it clear?
+
+69
+00:05:44,000 --> 00:05:52,000
+After that, I right join Kyra, as we discussed, I can admit you, Akiva, and specify tables that
+
+70
+00:05:52,000 --> 00:05:58,000
+I want to join again and ask for old table is specified next to the role table name.
+
+71
+00:05:59,000 --> 00:06:05,000
+And after that, I need to specify what rule will be used for my records in two different tables.
+
+72
+00:06:06,000 --> 00:06:10,000
+That's why I write on key word and specifies the rule.
+
+73
+00:06:11,000 --> 00:06:17,000
+I do field from rule table should match with the f k zero field from user table.
+
+74
+00:06:17,000 --> 00:06:23,000
+If you followed your course and you didn't miss previous lessons, you should remember that f k is a
+
+75
+00:06:23,000 --> 00:06:25,000
+rule is a foreign key.
+
+76
+00:06:26,000 --> 00:06:33,000
+Now, I am sure that this query will return US ballot information that's executable, and we see two
+
+77
+00:06:33,000 --> 00:06:39,000
+rows return on the last name and roll like we requested any questions.
+
+78
+00:06:39,000 --> 00:06:40,000
+So 14.
+
+79
+00:06:40,000 --> 00:06:45,000
+In case of any questions, please read them in comments below this video.
+
+80
+00:06:46,000 --> 00:06:48,000
+Now, let's discuss Order Jones.
+
+81
+00:06:49,000 --> 00:06:57,000
+So how is this author joining verbs, the Jones table three themes each row, even if no awesome marching
+
+82
+00:06:57,000 --> 00:06:58,000
+rule exists.
+
+83
+00:06:58,000 --> 00:07:07,000
+All author joins Subdivide further into left joints, writes joints and full order joints based on which
+
+84
+00:07:07,000 --> 00:07:09,000
+tables throw you would like to retain.
+
+85
+00:07:10,000 --> 00:07:13,000
+How to understand where is that and where is right table?
+
+86
+00:07:14,000 --> 00:07:21,000
+It depends on which side from joint keyword the name is specified as a result of left or the joint or
+
+87
+00:07:21,000 --> 00:07:22,000
+simply left.
+
+88
+00:07:22,000 --> 00:07:24,000
+Join for tables.
+
+89
+00:07:24,000 --> 00:07:32,000
+A and B always contains all rows of the lap table, even if the joint condition doesn't find any metric
+
+90
+00:07:32,000 --> 00:07:33,000
+row in the right table.
+
+91
+00:07:34,000 --> 00:07:41,000
+This means that these are all close matches, zero rows in the right table for a given row in the left
+
+92
+00:07:41,000 --> 00:07:41,000
+table.
+
+93
+00:07:42,000 --> 00:07:49,000
+The joint will still return a row in the result, but with no in each column from the right table and
+
+94
+00:07:49,000 --> 00:07:51,000
+left or the joint returns.
+
+95
+00:07:51,000 --> 00:07:59,000
+All the values from an integer plus all values in the left table that do not match through the right
+
+96
+00:07:59,000 --> 00:08:03,000
+table, including rows, was now well used in Zelinka column.
+
+97
+00:08:04,000 --> 00:08:09,000
+Is it clear the same principle applies to the right auto joint?
+
+98
+00:08:09,000 --> 00:08:16,000
+But in this case, we return all records from inner joint plus all records from right the bill, even
+
+99
+00:08:16,000 --> 00:08:23,000
+if they don't match to any record in left table and the last stop of order, John is full order junk
+
+100
+00:08:24,000 --> 00:08:32,000
+conceptual at full auto joint combines the effect of applying both left and right, or the joints and
+
+101
+00:08:32,000 --> 00:08:37,000
+throws that don't have Malcolm in the table will have no values in the result set.
+
+102
+00:08:38,000 --> 00:08:41,000
+Let's now review these types of joints one real example.
+
+103
+00:08:42,000 --> 00:08:43,000
+Let's start from the left, Joan.
+
+104
+00:08:44,000 --> 00:08:51,000
+Basically, we would take the same queries that we reviewed neurons in the demo and will add left keema.
+
+105
+00:08:52,000 --> 00:08:55,000
+Let's execute it now and see what will be returned.
+
+106
+00:08:56,000 --> 00:09:04,000
+And you can see that we received all last means from our user table that is on the left from joint keyword
+
+107
+00:09:04,000 --> 00:09:08,000
+and for records where any match wasn't found in row table.
+
+108
+00:09:09,000 --> 00:09:13,000
+We just returned now that's called left joint right.
+
+109
+00:09:13,000 --> 00:09:20,000
+June would look opposite way in this case, which on all road names, even if we don't have users assigned
+
+110
+00:09:20,000 --> 00:09:28,000
+to this row because the table is on the right from June Cleaver and this is right joint query, does
+
+111
+00:09:28,000 --> 00:09:29,000
+it make sense?
+
+112
+00:09:30,000 --> 00:09:32,000
+Now, let me show you a question.
+
+113
+00:09:32,000 --> 00:09:38,000
+We just remove credit cards and leave on the John Key take into account.
+
+114
+00:09:38,000 --> 00:09:42,000
+We have four records in user table and four records in Table.
+
+115
+00:09:43,000 --> 00:09:46,000
+We're going to receive in total 16 records.
+
+116
+00:09:46,000 --> 00:09:52,000
+Basically, each records from one table should be mapped was each row from another table.
+
+117
+00:09:53,000 --> 00:09:57,000
+We receive all possible combinations of wrappers from each table.
+
+118
+00:09:57,000 --> 00:10:04,000
+To be honest, this type of query is interesting to know from series side, but probably it has limited
+
+119
+00:10:04,000 --> 00:10:06,000
+areas for use in in business cases.
+
+120
+00:10:06,000 --> 00:10:11,000
+It is rare seeing when you need to find combinations between all records from two tables.
+
+121
+00:10:12,000 --> 00:10:16,000
+And the last but not least type of joint is full order.
+
+122
+00:10:17,000 --> 00:10:20,000
+In my school, it can be implemented with the help of union keyword.
+
+123
+00:10:21,000 --> 00:10:23,000
+What is Union Keyword?
+
+124
+00:10:23,000 --> 00:10:27,000
+It combines two queries in one single query to the database.
+
+125
+00:10:27,000 --> 00:10:32,000
+In our case, we need to combine two queries with two joints left and right.
+
+126
+00:10:32,000 --> 00:10:35,000
+And you can see that I connect to select statements.
+
+127
+00:10:35,000 --> 00:10:43,000
+Was Union Kuvira that's executed this query, and we can see that we received all full records from
+
+128
+00:10:43,000 --> 00:10:49,000
+user table and all four records from the row table, even despite not all the records have mapping.
+
+129
+00:10:50,000 --> 00:10:52,000
+This makes sense homes.
+
+130
+00:10:52,000 --> 00:10:53,000
+It's now with this example.
+
+131
+00:10:53,000 --> 00:10:58,000
+Things become clearer and we also learned how union works.
+
+132
+00:10:59,000 --> 00:11:03,000
+Usually, union is used when you are dealing with some archived data.
+
+133
+00:11:03,000 --> 00:11:11,000
+When you queries a main table and operational or table was archived data regarding joints important
+
+134
+00:11:11,000 --> 00:11:16,000
+things to know that in this way, you can join two and more tables.
+
+135
+00:11:17,000 --> 00:11:20,000
+This will become important when you will come to the homework task.
+
+136
+00:11:21,000 --> 00:11:24,000
+Imagines that you are dealing with many, many relationships.
+
+137
+00:11:24,000 --> 00:11:29,000
+In this case, you have three tables that the disconnect between each other.
+
+138
+00:11:29,000 --> 00:11:31,000
+This will be part of your home desk.
+
+139
+00:11:32,000 --> 00:11:35,000
+I will also provide you with solutions as a home task.
+
+140
+00:11:35,000 --> 00:11:39,000
+But I just want you to solve this task by itself first.
+
+141
+00:11:39,000 --> 00:11:44,000
+The only one more topics that I'd love to discuss with you today is sub queries.
+
+142
+00:11:44,000 --> 00:11:49,000
+This topic is too small for a separate lesson, but still important to know.
+
+143
+00:11:49,000 --> 00:11:51,000
+I want to explain some queries.
+
+144
+00:11:52,000 --> 00:11:56,000
+What if you would like to create condition was the result of another query.
+
+145
+00:11:57,000 --> 00:11:59,000
+You can do so with the help of sub queries.
+
+146
+00:12:00,000 --> 00:12:04,000
+A sub query is a sequel query nested inside a logic query.
+
+147
+00:12:05,000 --> 00:12:12,000
+Sub query is also called and even a query or in there, so that while the statements contained in the
+
+148
+00:12:12,000 --> 00:12:21,000
+sub query is also called an auto query or to select the inner query executes first before its parent
+
+149
+00:12:21,000 --> 00:12:27,000
+query so that the results of an inner query can be passed to the auto query.
+
+150
+00:12:28,000 --> 00:12:33,000
+You can use a sub query in a select insert, delete or update statements.
+
+151
+00:12:33,000 --> 00:12:39,000
+A sub query is usually added within the very close of another SQL select statement.
+
+152
+00:12:39,000 --> 00:12:45,000
+In our particular example, let's imagine that we want to extract users who have value in money column
+
+153
+00:12:45,000 --> 00:12:53,000
+more than average money value across all users before you would be able to execute this kind of query.
+
+154
+00:12:53,000 --> 00:12:56,000
+Let's make small adjustments in our tables.
+
+155
+00:12:56,000 --> 00:13:02,000
+I need to add money column and fill it out with data to make your life easier.
+
+156
+00:13:03,000 --> 00:13:08,000
+I prepared script for you that would add new column and populated with data.
+
+157
+00:13:09,000 --> 00:13:13,000
+I am going to leave the reference to this script in attachments to this lesson.
+
+158
+00:13:14,000 --> 00:13:19,000
+If you follow the course and you have the same structure, script will be executed without problem.
+
+159
+00:13:20,000 --> 00:13:28,000
+Pay attention to the data type of money column 15 mins amount of decimal digits and two means that only
+
+160
+00:13:28,000 --> 00:13:30,000
+two digits after point will be supported.
+
+161
+00:13:30,000 --> 00:13:38,000
+Considering mass around and rules, OK, so once you executed this script, your user table should look
+
+162
+00:13:38,000 --> 00:13:39,000
+like this.
+
+163
+00:13:40,000 --> 00:13:43,000
+Now let me damari you how sub query works.
+
+164
+00:13:44,000 --> 00:13:46,000
+We create regular select statements.
+
+165
+00:13:46,000 --> 00:13:52,000
+We want to receive rows where money is more than average money amount, and that counts of all users.
+
+166
+00:13:53,000 --> 00:13:59,000
+For this, I need to execute this sub query first understands the amount of money that can be used.
+
+167
+00:13:59,000 --> 00:14:03,000
+In my order query, I put Sequeira in parentheses.
+
+168
+00:14:04,000 --> 00:14:05,000
+Let's execute this query.
+
+169
+00:14:06,000 --> 00:14:13,000
+Our money amount was this specific test data will be around five hundred sixty four and we have two
+
+170
+00:14:13,000 --> 00:14:19,000
+rows returns with money amount higher as an average money amount than this.
+
+171
+00:14:19,000 --> 00:14:22,000
+Now you can work with sub queries.
+
+172
+00:14:23,000 --> 00:14:23,000
+That's all.
+
+173
+00:14:23,000 --> 00:14:24,000
+What I wanted to share.
+
+174
+00:14:24,000 --> 00:14:25,000
+Was you in this lesson?
+
+175
+00:14:26,000 --> 00:14:28,000
+Let's recap what we have learned today.
+
+176
+00:14:29,000 --> 00:14:36,000
+This lesson we learned what joints are after that we focus on different joint types moving around in
+
+177
+00:14:36,000 --> 00:14:40,000
+the water, across joints and reviewed SQL queries.
+
+178
+00:14:41,000 --> 00:14:47,000
+Now you know how to work with union keywords, and the answers will have some of you learned how to
+
+179
+00:14:47,000 --> 00:14:48,000
+work with subwoofers.
+
+180
+00:14:49,000 --> 00:14:50,000
+That's all for this lesson.
+
+181
+00:14:50,000 --> 00:14:52,000
+Thanks a lot for your attention.
+
+182
+00:14:52,000 --> 00:14:53,000
+Have a great day.
+
+183
+00:14:54,000 --> 00:14:55,000
+See you next lesson.
+

48 - SQL/003 Query-Examples-that-were-shown-in-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/dml/joins

48 - SQL/external-links.txt

@@ -0,0 +1,15 @@
+
+001 MySQL-Documentation-about-statements
+https://dev.mysql.com/doc/refman/8.0/en/create-view.html
+
+001 Query-Examples-that-were-shown-in-the-lesson
+https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/ddl
+
+002 INSERT-statement-documentation
+https://dev.mysql.com/doc/refman/8.0/en/insert.html
+
+002 Query-Examples-that-were-shown-in-the-lesson
+https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/dml
+
+003 Query-Examples-that-were-shown-in-the-lesson
+https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/dml/joins

49 - Relational Databases (Advanced)/001 Find-folders-with-Views-Triggers-Stored-Procedures-and-Stored-Functions-SQL-query-examples-here.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/ddl

49 - Relational Databases (Advanced)/001 Views, Triggers, Stored Procedures & Functions_en.srt

@@ -0,0 +1,1548 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:11,000
+And this last one, we're going to learn some new concepts in a relational databases.
+
+3
+00:00:11,000 --> 00:00:16,000
+I would explain what use triggers, stored procedures and stored functions are.
+
+4
+00:00:16,000 --> 00:00:23,000
+Also, you will understand why we need them and how to work with them on practice, because today will
+
+5
+00:00:23,000 --> 00:00:24,000
+have practical part, too.
+
+6
+00:00:25,000 --> 00:00:27,000
+So be prepared for interesting lesson.
+
+7
+00:00:28,000 --> 00:00:30,000
+We are going to go over each topic.
+
+8
+00:00:30,000 --> 00:00:37,000
+One by one and one will focus on practical examples of use triggers, stored procedures and storage
+
+9
+00:00:37,000 --> 00:00:37,000
+functions.
+
+10
+00:00:38,000 --> 00:00:44,000
+I'm going also to explain just some new syntax features like, for example, single line and multi line
+
+11
+00:00:44,000 --> 00:00:47,000
+commonsensical session variables.
+
+12
+00:00:47,000 --> 00:00:53,000
+Also, I'll show you how you can change the limiter between SQL statements in my signal.
+
+13
+00:00:53,000 --> 00:00:55,000
+Let's start our lesson.
+
+14
+00:00:55,000 --> 00:00:59,000
+And the first thing that I'd like to review with you in this video is viewed.
+
+15
+00:01:00,000 --> 00:01:03,000
+Let's understand first what is viewed in databases.
+
+16
+00:01:04,000 --> 00:01:06,000
+We use virtual tables.
+
+17
+00:01:06,000 --> 00:01:10,000
+There are only a structure and contain no data.
+
+18
+00:01:10,000 --> 00:01:15,000
+Their purpose is to allow a user to see a subset of the actual data.
+
+19
+00:01:16,000 --> 00:01:20,000
+You can consist of a subset of one or more tables.
+
+20
+00:01:20,000 --> 00:01:25,000
+What might be the reasons for creating and use zero might be different reasons.
+
+21
+00:01:26,000 --> 00:01:28,000
+Among the advantages of using the use, it is worse.
+
+22
+00:01:28,000 --> 00:01:31,000
+Dimension restricts the view of a table.
+
+23
+00:01:32,000 --> 00:01:39,000
+For example, you can create a view that contains not all fields, but only some of them that don't
+
+24
+00:01:39,000 --> 00:01:40,000
+have any sensitive data.
+
+25
+00:01:41,000 --> 00:01:48,000
+So you can hide some of columns in tables in larger organizations where many developers may be working
+
+26
+00:01:48,000 --> 00:01:49,000
+on a project.
+
+27
+00:01:49,000 --> 00:01:54,000
+We use allowed developers to access unused data they need.
+
+28
+00:01:55,000 --> 00:02:03,000
+June two or more tables and show it as one object to use it instead of constantly right in June, Junqueras,
+
+29
+00:02:03,000 --> 00:02:11,000
+you can create value for most often joins and lets user to watch the whole attributes as one database
+
+30
+00:02:11,000 --> 00:02:11,000
+object.
+
+31
+00:02:12,000 --> 00:02:19,000
+This also simplify life of developers, restricts the access of a table so that nobody can insert zeros
+
+32
+00:02:19,000 --> 00:02:23,000
+into the table is every single year so far.
+
+33
+00:02:23,000 --> 00:02:30,000
+Let's look at examples who you watched previous lessons because in this lesson, we're going to use
+
+34
+00:02:30,000 --> 00:02:33,000
+tables that were created during the course.
+
+35
+00:02:33,000 --> 00:02:37,000
+We're going to create value with you and configure it for our needs.
+
+36
+00:02:38,000 --> 00:02:44,000
+We'll create a view from my school workbench, I'm going to show you sequel queries it will create for
+
+37
+00:02:44,000 --> 00:02:52,000
+you, for us just to remind you, we have two tables here user table and roll table here.
+
+38
+00:02:52,000 --> 00:02:58,000
+How's it look like this great view with user email and droll name?
+
+39
+00:02:58,000 --> 00:03:04,000
+Because this is a dataset I use most often in my app urines and log in.
+
+40
+00:03:04,000 --> 00:03:10,000
+I use user email and also I need to understand user role to use this information for further interaction
+
+41
+00:03:10,000 --> 00:03:12,000
+inside our app.
+
+42
+00:03:12,000 --> 00:03:19,000
+That's why it might be a good year for me to create this view and simplify life of developers to let
+
+43
+00:03:19,000 --> 00:03:19,000
+them.
+
+44
+00:03:19,000 --> 00:03:23,000
+Where is this for you directly instead of creation on Junqueras?
+
+45
+00:03:24,000 --> 00:03:29,000
+And I believe you understood that this is a simple example was two tables only.
+
+46
+00:03:29,000 --> 00:03:37,000
+But in real life, you might create tables that use junk, whereas the five or even more tables, we
+
+47
+00:03:37,000 --> 00:03:44,000
+are going to start simple and let's create this view for two attributes from the tables.
+
+48
+00:03:45,000 --> 00:03:50,000
+The grades have you in my school workbench, I can click on the Create View icon.
+
+49
+00:03:50,000 --> 00:03:57,000
+Technically speaking, my school workbench just help us was one learn or create you statement and after
+
+50
+00:03:57,000 --> 00:04:01,000
+--, we need to specify sequel query for all of you.
+
+51
+00:04:02,000 --> 00:04:06,000
+I click Apply button and I execute this query.
+
+52
+00:04:06,000 --> 00:04:12,000
+Now the great I love you and you can find it here and the use in my school workbench.
+
+53
+00:04:13,000 --> 00:04:20,000
+Basically, you can perform select operations against this view is the same as you do against a table
+
+54
+00:04:21,000 --> 00:04:22,000
+in select statement.
+
+55
+00:04:22,000 --> 00:04:24,000
+You just use your name.
+
+56
+00:04:25,000 --> 00:04:27,000
+Let me now update our regional tables.
+
+57
+00:04:28,000 --> 00:04:33,000
+For example, let's paste one more record in user table was role assigned.
+
+58
+00:04:36,000 --> 00:04:42,000
+One rule is that it lets execute, select all query to our view one more time.
+
+59
+00:04:43,000 --> 00:04:45,000
+And you can see that view is also updated.
+
+60
+00:04:46,000 --> 00:04:47,000
+Isn't that cool?
+
+61
+00:04:48,000 --> 00:04:50,000
+And you don't need to constantly read joint statements.
+
+62
+00:04:51,000 --> 00:04:55,000
+Pay attention that I can't add new rules here in view.
+
+63
+00:04:55,000 --> 00:05:00,000
+So as we discussed, we often use views for select statements.
+
+64
+00:05:01,000 --> 00:05:03,000
+That's all what I wanted to share with you regarding the use.
+
+65
+00:05:04,000 --> 00:05:05,000
+Is it clear?
+
+66
+00:05:06,000 --> 00:05:12,000
+Even in the case you have any questions, please add them in comments below this video, and I will
+
+67
+00:05:12,000 --> 00:05:13,000
+be happy to answer.
+
+68
+00:05:14,000 --> 00:05:16,000
+Let's proceed with a new topic.
+
+69
+00:05:17,000 --> 00:05:24,000
+That's what triggers are and how we can use them, and trigger is a set of instructions that are automatically
+
+70
+00:05:24,000 --> 00:05:30,000
+activated in response to a specific event occurred on a table in the database.
+
+71
+00:05:30,000 --> 00:05:34,000
+The trigger is always associated with a particular table.
+
+72
+00:05:34,000 --> 00:05:39,000
+If the table is deleted, all the associated triggers are also deleted automatically.
+
+73
+00:05:40,000 --> 00:05:49,000
+The trigger is invoked either before or after the following event insert when a euro is inserted hamdard
+
+74
+00:05:49,000 --> 00:05:51,000
+when an existing row is updated.
+
+75
+00:05:51,000 --> 00:05:54,000
+Delete when the row is deleted.
+
+76
+00:05:54,000 --> 00:05:58,000
+When you submit for execution and insert, update or delete statement.
+
+77
+00:05:59,000 --> 00:06:05,000
+Zero Relational Database Management System FAS as a corresponding trigger, always remember is that
+
+78
+00:06:05,000 --> 00:06:11,000
+it can be two triggers with similar action time and event for one table.
+
+79
+00:06:12,000 --> 00:06:20,000
+For example, we can't have two before update triggers for a table, but we can have before update and
+
+80
+00:06:20,000 --> 00:06:28,000
+before insert trigger or before and after they trigger, let's review the structure of the Create Trigger
+
+81
+00:06:28,000 --> 00:06:34,000
+statement we write Great trigger first trigger name should be unique.
+
+82
+00:06:34,000 --> 00:06:40,000
+After that, we specify, was a trigger should be activated before or after some event occurs.
+
+83
+00:06:41,000 --> 00:06:45,000
+Then we need to specify on which event we want to activate.
+
+84
+00:06:45,000 --> 00:06:51,000
+Our instructions is insert the date or the lead in which table.
+
+85
+00:06:51,000 --> 00:06:54,000
+After that, we can specify for each role.
+
+86
+00:06:55,000 --> 00:06:57,000
+This specifies a role level trigger.
+
+87
+00:06:58,000 --> 00:07:02,000
+For example, the trigger will be executed for each role being affected.
+
+88
+00:07:03,000 --> 00:07:05,000
+We can add trigger order.
+
+89
+00:07:05,000 --> 00:07:12,000
+This option might be useful if we have chain of triggers and we need to control that order.
+
+90
+00:07:12,000 --> 00:07:19,000
+And after all this, we need to describe trigger body that is exactly a set of instructions that are
+
+91
+00:07:19,000 --> 00:07:20,000
+needed to be executed.
+
+92
+00:07:21,000 --> 00:07:22,000
+Is everything clear?
+
+93
+00:07:22,000 --> 00:07:27,000
+Let's look at our practical demo and create one trigger as an example.
+
+94
+00:07:28,000 --> 00:07:35,000
+We are going to come up with some imaginary business case, imagine before inserting new actors in user
+
+95
+00:07:35,000 --> 00:07:35,000
+table.
+
+96
+00:07:35,000 --> 00:07:42,000
+We want to check that in case there is no well specified for foreign key F-k user role, fields should
+
+97
+00:07:42,000 --> 00:07:44,000
+be populated in this valley.
+
+98
+00:07:44,000 --> 00:07:44,000
+Six.
+
+99
+00:07:45,000 --> 00:07:49,000
+Yes, I know that for such purpose, we can set up default value for field.
+
+100
+00:07:50,000 --> 00:07:56,000
+But I want you to focus on the syntax right now, and I just want to present your syntax as simple as
+
+101
+00:07:56,000 --> 00:08:00,000
+possible without overcomplicate and business logic.
+
+102
+00:08:00,000 --> 00:08:08,000
+So attention to the syntax and my comments as we go, there is one more syntax specifics.
+
+103
+00:08:09,000 --> 00:08:13,000
+You can see that I specified another the name of the double ampersand.
+
+104
+00:08:14,000 --> 00:08:22,000
+Usually, we use a semicolon to separate those statements when writing SQL statements and MySQL client
+
+105
+00:08:22,000 --> 00:08:29,000
+program such as My SQL Revenge uses limited to separate statements and execute each statement separately.
+
+106
+00:08:30,000 --> 00:08:38,000
+However, for example, a stored procedure or trigger consists of multiple statements separated by semicolon,
+
+107
+00:08:38,000 --> 00:08:45,000
+and it will use my SQL workbench to define a trigger like in this case that contains semicolon characters.
+
+108
+00:08:46,000 --> 00:08:52,000
+The most equal client program will not treat the whole stored procedure, create statement or the whole
+
+109
+00:08:52,000 --> 00:08:58,000
+trigger create statement as a single statement, but many statements.
+
+110
+00:08:59,000 --> 00:09:05,000
+Therefore, we must really finds that the limiter temporarily so that we can pause the whole trigger
+
+111
+00:09:05,000 --> 00:09:08,000
+description to the server as a single statement.
+
+112
+00:09:09,000 --> 00:09:13,000
+That's why I said You didn't DeMatha at the beginning of this statement.
+
+113
+00:09:13,000 --> 00:09:17,000
+Andrew Chan it back to default at the end of the statement.
+
+114
+00:09:18,000 --> 00:09:23,000
+Execute multiple statements which can place trigger body between Begin and and keywords.
+
+115
+00:09:24,000 --> 00:09:28,000
+Basically, you can put here I'm a date insert delete statements.
+
+116
+00:09:28,000 --> 00:09:32,000
+You can address those statements to any table you wish.
+
+117
+00:09:32,000 --> 00:09:41,000
+And also, you can make conditions like I do here, I write, if followed by a predicate, some expressions,
+
+118
+00:09:41,000 --> 00:09:43,000
+a three chance is a true or false.
+
+119
+00:09:43,000 --> 00:09:49,000
+In this particular case, before inserting new value, I verifies its new value as it is going to be
+
+120
+00:09:49,000 --> 00:09:53,000
+inserted is not within the trigger body.
+
+121
+00:09:53,000 --> 00:09:56,000
+We can refer to columns in the subject table.
+
+122
+00:09:57,000 --> 00:10:02,000
+That is the table associated with the trigger by using the aliases.
+
+123
+00:10:02,000 --> 00:10:11,000
+Old and new art and column name refers to column often exists in the road before it is updated or deleted.
+
+124
+00:10:12,000 --> 00:10:19,000
+You and column the very first is a column often, you know, to be inserted or an existing row after
+
+125
+00:10:19,000 --> 00:10:20,000
+it is updated.
+
+126
+00:10:20,000 --> 00:10:21,000
+Does it make sense?
+
+127
+00:10:22,000 --> 00:10:28,000
+In the East Block, we can write any statements we wish, considering that we override the limit, that
+
+128
+00:10:28,000 --> 00:10:35,000
+we can use semicolon here to separate statements between each other at the end of the statement, I
+
+129
+00:10:35,000 --> 00:10:37,000
+should specify and if?
+
+130
+00:10:38,000 --> 00:10:44,000
+Once I declared all statements and about it, I should close triggered by what it was and the keyword.
+
+131
+00:10:45,000 --> 00:10:49,000
+And as we already discussed, I want to return the limits back to the fold.
+
+132
+00:10:50,000 --> 00:10:51,000
+Let's execute the statement.
+
+133
+00:10:52,000 --> 00:10:58,000
+And I see that query has been executed successfully and trigger is created.
+
+134
+00:10:59,000 --> 00:11:04,000
+You can check all existing triggers and this is where my SQL workbench do mouse.
+
+135
+00:11:04,000 --> 00:11:08,000
+Right click on the table and select out a table.
+
+136
+00:11:09,000 --> 00:11:14,000
+And on the three year tab, you can find all existing triggers to delete trigger.
+
+137
+00:11:14,000 --> 00:11:18,000
+You can click Mouse, right click and select Delete Trigger.
+
+138
+00:11:19,000 --> 00:11:25,000
+You can move the order of triggers here if you have multiple triggers, duplicate triggers, if needed,
+
+139
+00:11:25,000 --> 00:11:25,000
+and so on.
+
+140
+00:11:26,000 --> 00:11:28,000
+Let's see how trigger works.
+
+141
+00:11:29,000 --> 00:11:34,000
+So I add new records and deliberately leaving F-k user role at any time.
+
+142
+00:11:35,000 --> 00:11:43,000
+Let me apply changes and after changes applied, you can see that six has been added by default.
+
+143
+00:11:43,000 --> 00:11:51,000
+So before insertion, my triggers set the value to zero records is that I was about to act and only
+
+144
+00:11:51,000 --> 00:11:56,000
+after that insertion happened and I received a result like this.
+
+145
+00:11:57,000 --> 00:12:03,000
+In conclusion of triggers discussion, it is worth to mention some drawbacks of using triggers.
+
+146
+00:12:04,000 --> 00:12:08,000
+The main problem with triggers are they are completely global.
+
+147
+00:12:08,000 --> 00:12:16,000
+If you create a trigger to react on insertion event, that means that this rule will be applied to any
+
+148
+00:12:16,000 --> 00:12:19,000
+kind of insertion event without possibility.
+
+149
+00:12:19,000 --> 00:12:24,000
+Make an exclusion, at least sometimes logic on that the base layer.
+
+150
+00:12:24,000 --> 00:12:32,000
+Remember that creating triggers on the database layer you want your logic, the specific database and
+
+151
+00:12:32,000 --> 00:12:36,000
+then some degree detach your business logic from your app.
+
+152
+00:12:37,000 --> 00:12:44,000
+While triggers not always contain business rules and may be important piece in supporting of data consistency
+
+153
+00:12:44,000 --> 00:12:44,000
+database.
+
+154
+00:12:45,000 --> 00:12:51,000
+This is not always the case, and in case you make decisions, migrate to another database management
+
+155
+00:12:51,000 --> 00:12:52,000
+system.
+
+156
+00:12:52,000 --> 00:12:56,000
+It may become a pain to not lose any important operation.
+
+157
+00:12:56,000 --> 00:12:59,000
+Already scrapped and triggers triggers.
+
+158
+00:12:59,000 --> 00:13:02,000
+I still see by saying this.
+
+159
+00:13:02,000 --> 00:13:09,000
+I mean that it is easy to forget that there until they hurt you with unintended and very mysterious
+
+160
+00:13:09,000 --> 00:13:10,000
+consequences.
+
+161
+00:13:11,000 --> 00:13:14,000
+All this doesn't mean that you should never use triggers.
+
+162
+00:13:14,000 --> 00:13:21,000
+You just need to be aware of about this potential impact and use triggers carefully and wisely.
+
+163
+00:13:22,000 --> 00:13:25,000
+If everything is clear, let's move on.
+
+164
+00:13:26,000 --> 00:13:28,000
+Now, let's talk about stored procedures.
+
+165
+00:13:29,000 --> 00:13:32,000
+Let's learn what are they and how to work with them.
+
+166
+00:13:33,000 --> 00:13:37,000
+The start of procedure is a prepared sequel code is that you can see.
+
+167
+00:13:37,000 --> 00:13:40,000
+So the court can be reused over and over again.
+
+168
+00:13:41,000 --> 00:13:49,000
+So if you have an equal query that you write over and over again, save it as a stored procedure and
+
+169
+00:13:49,000 --> 00:13:51,000
+then just call it to execute it.
+
+170
+00:13:52,000 --> 00:13:59,000
+You can also put parameters to this procedure so that the procedure can act based on the parameter values
+
+171
+00:13:59,000 --> 00:14:00,000
+is at a sparse.
+
+172
+00:14:01,000 --> 00:14:05,000
+So what advantages of storage procedures performance?
+
+173
+00:14:06,000 --> 00:14:13,000
+The SQL server stored procedure when executed for the first time, creates a plan and stores it in the
+
+174
+00:14:13,000 --> 00:14:18,000
+buffer pool so that plan can be reused when it executes next time.
+
+175
+00:14:19,000 --> 00:14:25,000
+Reusable storage procedures can be executed by multiple users or multiple client applications without
+
+176
+00:14:25,000 --> 00:14:27,000
+the need of writing the code again.
+
+177
+00:14:28,000 --> 00:14:30,000
+It can be easily modified.
+
+178
+00:14:30,000 --> 00:14:37,000
+We can easily modify the code inside the stored procedure without the need to restart or deploying the
+
+179
+00:14:37,000 --> 00:14:39,000
+application security.
+
+180
+00:14:40,000 --> 00:14:45,000
+Stored procedures reduce this threat by eliminating direct access to the tables.
+
+181
+00:14:46,000 --> 00:14:53,000
+We can also encrypt the storage procedures while creating them so that source code and signs are stored.
+
+182
+00:14:53,000 --> 00:14:54,000
+Procedures not visible.
+
+183
+00:14:55,000 --> 00:14:57,000
+Reduced network traffic.
+
+184
+00:14:58,000 --> 00:15:04,000
+One When we use stored procedures instead of writing SQL queries as the application level only has a
+
+185
+00:15:04,000 --> 00:15:08,000
+procedure, name is passed over the network instead of the whole cycle code.
+
+186
+00:15:09,000 --> 00:15:13,000
+In of procedures, we can pass in and out parameters.
+
+187
+00:15:14,000 --> 00:15:18,000
+There are three types of parameters that we can pass and start procedures.
+
+188
+00:15:18,000 --> 00:15:27,000
+They are in, out and in, out in is an input only parameters which provide values to the storage procedure.
+
+189
+00:15:28,000 --> 00:15:31,000
+In addition, the value of in parameter is protected.
+
+190
+00:15:32,000 --> 00:15:39,000
+It means that even if you change the value of the parameter inside the stored procedure, its original
+
+191
+00:15:39,000 --> 00:15:43,000
+value is unchanged after the procedure ends.
+
+192
+00:15:44,000 --> 00:15:52,000
+In other words, the third procedure only works on the copy of in parameter and in parameter processing
+
+193
+00:15:52,000 --> 00:15:52,000
+value.
+
+194
+00:15:52,000 --> 00:15:59,000
+In the procedure, the procedure might modify the value, but the modification is not visible to the
+
+195
+00:15:59,000 --> 00:16:02,000
+caller when the procedure returns.
+
+196
+00:16:03,000 --> 00:16:10,000
+Out is output only parameters, which return values from this procedure, there's a Call-In program,
+
+197
+00:16:11,000 --> 00:16:18,000
+the value of an out parameter can be changed inside the stored procedure, and its new value is passed
+
+198
+00:16:18,000 --> 00:16:25,000
+back to IT program an out parameter processing value from the procedure back to the collar.
+
+199
+00:16:25,000 --> 00:16:31,000
+Its initial value is not within the procedure and its value is usable to the collar.
+
+200
+00:16:31,000 --> 00:16:34,000
+Was the procedure a chance you now?
+
+201
+00:16:34,000 --> 00:16:42,000
+It is an input and output parameters which provides values to and returns values from the stored procedure.
+
+202
+00:16:43,000 --> 00:16:46,000
+This is a combination of in and out parameters.
+
+203
+00:16:46,000 --> 00:16:53,000
+It means that the Coghlin program may cost the argument, and the stored procedure can modify the invalid
+
+204
+00:16:53,000 --> 00:17:00,000
+parameter and pass the new value back to the Collins program and out parameter is initialized by the
+
+205
+00:17:00,000 --> 00:17:07,000
+collar can be modified by the procedure, and any change made by the procedure is visible to the caller.
+
+206
+00:17:08,000 --> 00:17:16,000
+Once the procedure returns for each out or in that parameter, boss a user defined variable in the call
+
+207
+00:17:16,000 --> 00:17:23,000
+statement that involves the procedure so that you can obtain its value once the procedure returns.
+
+208
+00:17:23,000 --> 00:17:30,000
+If you are calling the procedure from within and not the stored procedure function, you can also pass
+
+209
+00:17:30,000 --> 00:17:35,000
+a routine parameter or local routine variable as an out or an out parameter.
+
+210
+00:17:36,000 --> 00:17:42,000
+If you are calling the procedure from within a trigger, you can also pass new column name as an out
+
+211
+00:17:42,000 --> 00:17:44,000
+or in that parameter.
+
+212
+00:17:44,000 --> 00:17:50,000
+The parameter leased and close was in parentheses must always be present.
+
+213
+00:17:50,000 --> 00:17:57,000
+If there are no parameters and empty parameters, at least should be used, parameter names are not
+
+214
+00:17:57,000 --> 00:17:58,000
+case sensitive.
+
+215
+00:17:59,000 --> 00:18:04,000
+Each parameter is an in parameter by default to specify otherwise for a parameter.
+
+216
+00:18:04,000 --> 00:18:08,000
+Use the keywords out or in out before the parameter name.
+
+217
+00:18:09,000 --> 00:18:15,000
+Don't worry if you are not feeling confident about understanding of different parameter types, we are
+
+218
+00:18:15,000 --> 00:18:21,000
+going to have them soon and it will be easier to understand was examples if you understood the theory
+
+219
+00:18:21,000 --> 00:18:24,000
+of stored procedures and why we need them.
+
+220
+00:18:24,000 --> 00:18:26,000
+Let's hold a demo.
+
+221
+00:18:27,000 --> 00:18:29,000
+Let's create a simple procedure.
+
+222
+00:18:29,000 --> 00:18:32,000
+Our procedure will select the user by email.
+
+223
+00:18:32,000 --> 00:18:36,000
+You already know why I set different animals are in my school query.
+
+224
+00:18:37,000 --> 00:18:40,000
+The reason is the same as an example with triggers.
+
+225
+00:18:41,000 --> 00:18:43,000
+Here's an example was in parameter.
+
+226
+00:18:44,000 --> 00:18:51,000
+Important thing to remember Bear tensions at the name of the parameter and name of column in where clause
+
+227
+00:18:51,000 --> 00:18:52,000
+should be different.
+
+228
+00:18:52,000 --> 00:18:59,000
+You know, the server would understand where you referred the parameter and where you refer to the column.
+
+229
+00:19:00,000 --> 00:19:06,000
+After that, I right begin keywords and after that go start procedure body.
+
+230
+00:19:06,000 --> 00:19:08,000
+Well, we can specify our instructions.
+
+231
+00:19:09,000 --> 00:19:11,000
+One procedure body is finished.
+
+232
+00:19:11,000 --> 00:19:13,000
+We use and keywords.
+
+233
+00:19:16,000 --> 00:19:24,000
+Now we can easily execute this stored procedure with the help of coal keywords and possibly the email
+
+234
+00:19:24,000 --> 00:19:28,000
+parameter in case we wouldn't pass email parameter.
+
+235
+00:19:28,000 --> 00:19:33,000
+We would see error that would tell us about wrong number of parameters.
+
+236
+00:19:34,000 --> 00:19:38,000
+And here is record with the correct email has been returned.
+
+237
+00:19:38,000 --> 00:19:41,000
+Do understand how to create stored procedure and how to call it.
+
+238
+00:19:42,000 --> 00:19:48,000
+As you can see, there is nothing complex in this, but probably a few questions still in the eye at
+
+239
+00:19:48,000 --> 00:19:51,000
+how the work was out and in parameters.
+
+240
+00:19:51,000 --> 00:19:52,000
+Correct.
+
+241
+00:19:53,000 --> 00:19:53,000
+As I promised you.
+
+242
+00:19:54,000 --> 00:19:57,000
+Let me show a practical example with these types of parameters.
+
+243
+00:19:58,000 --> 00:20:04,000
+Let's create procedure now that will return us average amount of money in our parameter.
+
+244
+00:20:04,000 --> 00:20:08,000
+As you can see, I vividly specifies that this is out parameter.
+
+245
+00:20:09,000 --> 00:20:17,000
+And after that inside procedure, I use into key words to stores the result into the out parameter.
+
+246
+00:20:18,000 --> 00:20:18,000
+Is that clear?
+
+247
+00:20:19,000 --> 00:20:21,000
+You should be familiar with this query.
+
+248
+00:20:22,000 --> 00:20:25,000
+This is aggregate functions that you reviewed in a separate lesson.
+
+249
+00:20:26,000 --> 00:20:32,000
+So in case you want to learn more about average and aggregate functions, feel free to review previous
+
+250
+00:20:32,000 --> 00:20:36,000
+lessons in the same way we create this stored procedure.
+
+251
+00:20:37,000 --> 00:20:43,000
+And now let's learn what is different during the invocation of this stored procedure when we call our
+
+252
+00:20:43,000 --> 00:20:44,000
+stored procedure.
+
+253
+00:20:45,000 --> 00:20:53,000
+We pass so-called session variable as a parameter to receive returns value because we need that reference
+
+254
+00:20:53,000 --> 00:20:56,000
+to the variable to retrieve a result of a storage procedure.
+
+255
+00:20:56,000 --> 00:21:04,000
+Execution A session variable is a user defined variables that starts was at sine doesn't require declaration
+
+256
+00:21:05,000 --> 00:21:12,000
+can be used in any SQL query or statement non-visible to other sessions and exists until the end of
+
+257
+00:21:12,000 --> 00:21:13,000
+the current session.
+
+258
+00:21:14,000 --> 00:21:19,000
+And after that, we can refer to this variable to get the value that was recorded into it.
+
+259
+00:21:20,000 --> 00:21:23,000
+I use simple select statement Does it make sense?
+
+260
+00:21:24,000 --> 00:21:26,000
+Is it not clear now home?
+
+261
+00:21:26,000 --> 00:21:27,000
+That was this example.
+
+262
+00:21:27,000 --> 00:21:30,000
+It is not clear how to use our parameter.
+
+263
+00:21:31,000 --> 00:21:34,000
+It looks like I have one more parameter type to show.
+
+264
+00:21:35,000 --> 00:21:37,000
+Let me show you example of in-out parameter.
+
+265
+00:21:38,000 --> 00:21:42,000
+In this example, we are going to implement counter stored procedure.
+
+266
+00:21:43,000 --> 00:21:49,000
+This procedure will take input parameter, will increase it by the specified amount and will return
+
+267
+00:21:49,000 --> 00:21:54,000
+as a value in the body of our stored procedure will incremento account.
+
+268
+00:21:55,000 --> 00:21:56,000
+That's it.
+
+269
+00:21:57,000 --> 00:22:04,000
+Let's look how we work with this kind of stored procedures and declare a session variable and initialize
+
+270
+00:22:04,000 --> 00:22:05,000
+it with some value.
+
+271
+00:22:06,000 --> 00:22:12,000
+After that, I call my stored procedure a few times by passing the same session variable and incremental
+
+272
+00:22:12,000 --> 00:22:12,000
+value.
+
+273
+00:22:13,000 --> 00:22:18,000
+After all this, I can read my session variable to find that it was incremented.
+
+274
+00:22:19,000 --> 00:22:25,000
+That proves that the state of our counter session variable was modified multiple times is every single
+
+275
+00:22:25,000 --> 00:22:26,000
+year.
+
+276
+00:22:26,000 --> 00:22:33,000
+And by the way, I have never shown you before how to request comments in my school robberies is just
+
+277
+00:22:33,000 --> 00:22:38,000
+below neat in this the different types of comments that you can use in my school.
+
+278
+00:22:39,000 --> 00:22:42,000
+First kind of comments that you can see here is double dash.
+
+279
+00:22:42,000 --> 00:22:45,000
+The comments must be at the end of a line.
+
+280
+00:22:45,000 --> 00:22:49,000
+Your SQL statement was a line break off the list.
+
+281
+00:22:49,000 --> 00:22:56,000
+Mazeltov comment and can only span a single line was in your school statement and must be at the end
+
+282
+00:22:56,000 --> 00:22:57,000
+of the line.
+
+283
+00:22:58,000 --> 00:23:01,000
+Another type of comment is similar to the previous one.
+
+284
+00:23:01,000 --> 00:23:06,000
+Just one more syntax of a single line comment started with a no sign.
+
+285
+00:23:07,000 --> 00:23:10,000
+Also, you can use Mutula in common in multi-line comment.
+
+286
+00:23:10,000 --> 00:23:14,000
+You should specify where a comment is started and where it is finished.
+
+287
+00:23:15,000 --> 00:23:22,000
+I'm not showing you how to alter and drop stored procedures because it is similar to dropping and altering
+
+288
+00:23:22,000 --> 00:23:24,000
+other database objects.
+
+289
+00:23:24,000 --> 00:23:28,000
+Just click mouse rightly constraint procedure that you are interested in.
+
+290
+00:23:29,000 --> 00:23:32,000
+Well, that it's regarding this example.
+
+291
+00:23:33,000 --> 00:23:38,000
+And now let's talk about functions and understand how they're different from stored procedures.
+
+292
+00:23:39,000 --> 00:23:45,000
+A function in my school is a program that is used to perform an action such as complex calculations,
+
+293
+00:23:46,000 --> 00:23:49,000
+for example, and returns the result of an action as a value.
+
+294
+00:23:50,000 --> 00:23:52,000
+Does it look like something similar to you?
+
+295
+00:23:53,000 --> 00:23:55,000
+Something what we have just discussed.
+
+296
+00:23:56,000 --> 00:24:01,000
+You are not the only one who wants to understand the difference between stored procedure and functions
+
+297
+00:24:01,000 --> 00:24:01,000
+and sequel.
+
+298
+00:24:02,000 --> 00:24:06,000
+Wait for a minute, and I will explain in detail what exactly the difference is.
+
+299
+00:24:07,000 --> 00:24:10,000
+There are two types of functions available in my sequel.
+
+300
+00:24:11,000 --> 00:24:15,000
+They are system defined functions and user defined functions.
+
+301
+00:24:16,000 --> 00:24:22,000
+We'll discuss system defined functions and a separate lesson, the function, which is defined by a
+
+302
+00:24:22,000 --> 00:24:25,000
+user, is called a user defined function.
+
+303
+00:24:26,000 --> 00:24:33,000
+My skill user defined functions may or may not have parameters at the optional, but it always returns
+
+304
+00:24:33,000 --> 00:24:35,000
+a single value that is mandatory.
+
+305
+00:24:36,000 --> 00:24:42,000
+The returned value which is returned by then my single function can be often an invalid.
+
+306
+00:24:42,000 --> 00:24:45,000
+My SQL data type regarding parameters and function.
+
+307
+00:24:46,000 --> 00:24:48,000
+Hammerson is much single isn't stored procedures.
+
+308
+00:24:49,000 --> 00:24:56,000
+You don't have different types of parameters like E out or announce all parameters and functions registered
+
+309
+00:24:56,000 --> 00:24:57,000
+as any parameters.
+
+310
+00:24:58,000 --> 00:25:02,000
+Now let's review high level syntax of great function statement.
+
+311
+00:25:02,000 --> 00:25:07,000
+First of all, specifies the name of the search function that you want to create after create function
+
+312
+00:25:07,000 --> 00:25:08,000
+keywords.
+
+313
+00:25:09,000 --> 00:25:15,000
+Secondly, list all parameters of the storage function inside the parentheses, followed by the function
+
+314
+00:25:15,000 --> 00:25:15,000
+name.
+
+315
+00:25:16,000 --> 00:25:21,000
+And as we have discussed by default, all parameters are the end parameters.
+
+316
+00:25:21,000 --> 00:25:30,000
+We can't specify in, out or in that modifies the parameters such centered specifies the data type of
+
+317
+00:25:30,000 --> 00:25:35,000
+the return value in the returns statement, which can be an invalid my school data type.
+
+318
+00:25:36,000 --> 00:25:44,000
+Force specify if a function is deterministic or not, using such deterministic keyword and deterministic
+
+319
+00:25:44,000 --> 00:25:50,000
+function always returns the same result for the same input parameters, whereas a non deterministic
+
+320
+00:25:50,000 --> 00:25:54,000
+function returns different results for the same input parameters.
+
+321
+00:25:55,000 --> 00:26:02,000
+If you don't use deterministic or not deterministic, my cycle uses are not deterministic option by
+
+322
+00:26:02,000 --> 00:26:10,000
+default, fifths rides are caught in the body of the storage function in the begin and block inside
+
+323
+00:26:10,000 --> 00:26:10,000
+them.
+
+324
+00:26:10,000 --> 00:26:11,000
+What is section?
+
+325
+00:26:11,000 --> 00:26:14,000
+You need to specify at least one return statement.
+
+326
+00:26:14,000 --> 00:26:20,000
+Zero chance statements returns a value to the call and programs when there was a written statement is
+
+327
+00:26:20,000 --> 00:26:21,000
+reached.
+
+328
+00:26:21,000 --> 00:26:25,000
+Six Kusum of the storage function is terminated immediately.
+
+329
+00:26:26,000 --> 00:26:31,000
+Let's look at the demo of functions now and after that will somes a difference.
+
+330
+00:26:31,000 --> 00:26:31,000
+A step.
+
+331
+00:26:32,000 --> 00:26:38,000
+And now example, let's create a function that can identify user status based on the amount of money
+
+332
+00:26:38,000 --> 00:26:40,000
+he or she has.
+
+333
+00:26:40,000 --> 00:26:43,000
+The function will take money as method argument.
+
+334
+00:26:43,000 --> 00:26:46,000
+It will return the value of virtual data type.
+
+335
+00:26:47,000 --> 00:26:49,000
+This is deterministic function.
+
+336
+00:26:50,000 --> 00:26:56,000
+We declare a variable and dependent on the amount of money we initialize this variable with one or another
+
+337
+00:26:56,000 --> 00:26:56,000
+value.
+
+338
+00:26:57,000 --> 00:27:04,000
+And at the end of the function body, when returns of value is ever seen clear here, please press a
+
+339
+00:27:04,000 --> 00:27:07,000
+pause if you want to look at all lines more thoroughly.
+
+340
+00:27:08,000 --> 00:27:12,000
+We executed this SQL statement and we have a function created.
+
+341
+00:27:13,000 --> 00:27:20,000
+You can easily list and review all functions that exist in the database, like this show function status
+
+342
+00:27:21,000 --> 00:27:22,000
+and specifies the database.
+
+343
+00:27:23,000 --> 00:27:27,000
+We can see that in our database, only one function is declared so far.
+
+344
+00:27:28,000 --> 00:27:29,000
+Let's invoke it now.
+
+345
+00:27:30,000 --> 00:27:36,000
+And you can already find one more difference between search function and storage procedure different
+
+346
+00:27:36,000 --> 00:27:43,000
+from a stored procedure, you can use a stored function in SQL statements wherever an expression is
+
+347
+00:27:43,000 --> 00:27:44,000
+used.
+
+348
+00:27:44,000 --> 00:27:49,000
+This helps improve the readability and mental ability of the procedural code.
+
+349
+00:27:50,000 --> 00:27:57,000
+In our example, I want to extract last name of user management and get the result of my function for
+
+350
+00:27:57,000 --> 00:27:57,000
+each record.
+
+351
+00:27:58,000 --> 00:28:02,000
+You can see that I invoke function here and post-money value to it.
+
+352
+00:28:03,000 --> 00:28:04,000
+Let's see what we'll get.
+
+353
+00:28:05,000 --> 00:28:09,000
+And you can see that as a result, we get what we expected.
+
+354
+00:28:09,000 --> 00:28:15,000
+Function has been applied to each record and returns us correct status for each user.
+
+355
+00:28:15,000 --> 00:28:16,000
+Then the stent.
+
+356
+00:28:16,000 --> 00:28:19,000
+Now how to create and execute function.
+
+357
+00:28:19,000 --> 00:28:21,000
+If yes, Zenith is great.
+
+358
+00:28:22,000 --> 00:28:28,000
+Now, when you saw functions and stored procedures, let's summarize what the difference is between
+
+359
+00:28:28,000 --> 00:28:28,000
+them.
+
+360
+00:28:29,000 --> 00:28:33,000
+There are numerous differences between storage procedures and storage functions.
+
+361
+00:28:34,000 --> 00:28:34,000
+That's true.
+
+362
+00:28:34,000 --> 00:28:41,000
+Using important ones, the function must return the value, but in standard procedure, it is optional
+
+363
+00:28:41,000 --> 00:28:42,000
+in the procedure.
+
+364
+00:28:42,000 --> 00:28:48,000
+We can return zero or and various functions can have on the input parameters for it.
+
+365
+00:28:49,000 --> 00:28:52,000
+Various procedures can have input or output parameters.
+
+366
+00:28:53,000 --> 00:29:00,000
+Functions can be called from procedure, whereas procedures cannot be called from a function.
+
+367
+00:29:01,000 --> 00:29:09,000
+The procedure allows select as well as insert update delete statements in it, whereas function allows
+
+368
+00:29:09,000 --> 00:29:10,000
+only a select statement in it.
+
+369
+00:29:11,000 --> 00:29:19,000
+Procedures can be utilized in a select statement, whereas function can be embedded in that select statement.
+
+370
+00:29:19,000 --> 00:29:27,000
+Stored procedures can't be used in the sequel statements anywhere in the where having select section
+
+371
+00:29:28,000 --> 00:29:35,000
+various function can be an exception can be handled by try catch block in the procedure, whereas try
+
+372
+00:29:35,000 --> 00:29:38,000
+catch block can't be used in a function.
+
+373
+00:29:39,000 --> 00:29:45,000
+We can use transactions in procedure, whereas we can't use transactions in function.
+
+374
+00:29:46,000 --> 00:29:49,000
+I believe that we captured and review of the main differences.
+
+375
+00:29:50,000 --> 00:29:52,000
+That's all for this lesson.
+
+376
+00:29:52,000 --> 00:29:56,000
+Let's recap what we have learned in the video today.
+
+377
+00:29:56,000 --> 00:29:58,000
+We have learned what views are.
+
+378
+00:29:58,000 --> 00:30:02,000
+We created our custom views and based on our existing tables.
+
+379
+00:30:02,000 --> 00:30:08,000
+I explained to you what triggers are now you know, how to create and work with stored procedures.
+
+380
+00:30:09,000 --> 00:30:16,000
+As we reviewed the examples, we learned different types of comments in Sequel Dilemma during my SQL
+
+381
+00:30:16,000 --> 00:30:17,000
+and session variables.
+
+382
+00:30:18,000 --> 00:30:25,000
+At the end of the lesson, we have learned functions and we learnt differences between functions and
+
+383
+00:30:25,000 --> 00:30:26,000
+stored procedures.
+
+384
+00:30:26,000 --> 00:30:28,000
+That's all for today.
+
+385
+00:30:28,000 --> 00:30:30,000
+Thanks a lot for your attention.
+
+386
+00:30:30,000 --> 00:30:31,000
+Have a great day.
+
+387
+00:30:31,000 --> 00:30:33,000
+See you in the next lesson.
+

49 - Relational Databases (Advanced)/002 MySQL Workbench Administration_en.srt

@@ -0,0 +1,508 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:06,000 --> 00:00:09,000
+In this lesson, we're going to learn database administration.
+
+3
+00:00:10,000 --> 00:00:15,000
+We're going to learn how to configure users random necessary rights to perform actions and database
+
+4
+00:00:16,000 --> 00:00:21,000
+how to track database performance, manage data expert and data inputs.
+
+5
+00:00:21,000 --> 00:00:27,000
+Definitely, this lesson is going to be interesting and useful for you in this lesson.
+
+6
+00:00:27,000 --> 00:00:32,000
+I'm going to do a lot of screen sharing on the example of my school workbench.
+
+7
+00:00:32,000 --> 00:00:39,000
+I'm going to show you how easily you can perform such basic operations as data import expert, new user
+
+8
+00:00:39,000 --> 00:00:46,000
+creation, configuring the and access for new account and track, or my SQL server performance.
+
+9
+00:00:46,000 --> 00:00:47,000
+Let's stop.
+
+10
+00:00:47,000 --> 00:00:53,000
+And as I already said today, we're going to have a lot of them examples on screen sharing.
+
+11
+00:00:53,000 --> 00:00:55,000
+So let me start sharing my screen.
+
+12
+00:00:56,000 --> 00:00:59,000
+Let's start from learning data expert and data input.
+
+13
+00:01:00,000 --> 00:01:06,000
+First of all, I want to show you a few menus and apps in my school workbench here, where for administration
+
+14
+00:01:06,000 --> 00:01:12,000
+tap and under management section, you can find data experts and data options.
+
+15
+00:01:13,000 --> 00:01:18,000
+Also, you can click on several menu to find data expert and data in-person options.
+
+16
+00:01:18,000 --> 00:01:19,000
+Why we need this.
+
+17
+00:01:20,000 --> 00:01:26,000
+For example, you need to configure a local database and populated with necessary data from production
+
+18
+00:01:26,000 --> 00:01:27,000
+environments.
+
+19
+00:01:28,000 --> 00:01:31,000
+These are for local development, debugging or any other purpose.
+
+20
+00:01:32,000 --> 00:01:40,000
+You do data experts in one place and do data in court in your local database, or imagine that you developed
+
+21
+00:01:40,000 --> 00:01:43,000
+your app and create a database structure.
+
+22
+00:01:43,000 --> 00:01:47,000
+And now it is time to go live and move to a production environment.
+
+23
+00:01:48,000 --> 00:01:54,000
+And as an example, let's imagine that we need to do experts of our learning database and all datasets
+
+24
+00:01:54,000 --> 00:01:56,000
+we created during the previous lessons.
+
+25
+00:01:57,000 --> 00:02:00,000
+Data expert I need to select database.
+
+26
+00:02:01,000 --> 00:02:04,000
+And when I select a database, I can select tables that I want to export.
+
+27
+00:02:05,000 --> 00:02:12,000
+Now, pay attention here if I want to initialize my database and production firm, and I don't need
+
+28
+00:02:12,000 --> 00:02:13,000
+test data at all.
+
+29
+00:02:14,000 --> 00:02:15,000
+I have few options here.
+
+30
+00:02:16,000 --> 00:02:22,000
+Namely, I can dump structure only if you need both data and structure.
+
+31
+00:02:23,000 --> 00:02:27,000
+You can select the option that will tell my school to dump data and structure.
+
+32
+00:02:28,000 --> 00:02:35,000
+Below, you can find check boxes that allow you to indicate whether you are ready to export stored procedures,
+
+33
+00:02:35,000 --> 00:02:37,000
+functions, triggers, events.
+
+34
+00:02:38,000 --> 00:02:44,000
+Below, you can find check boxes that allow you to indicate whether you want to export stored procedures.
+
+35
+00:02:44,000 --> 00:02:48,000
+Functions triggers events in exports options.
+
+36
+00:02:48,000 --> 00:02:54,000
+You can specify Project Folder for the dump in case you would specify Project Folder.
+
+37
+00:02:54,000 --> 00:03:01,000
+Each table will be exported as a separate file in case you select export self-contained file.
+
+38
+00:03:01,000 --> 00:03:05,000
+All instructions will be export that single file.
+
+39
+00:03:05,000 --> 00:03:09,000
+Pay attention that on my screen and probably on your stoop.
+
+40
+00:03:10,000 --> 00:03:13,000
+It is not possible to investigate all possible configurations.
+
+41
+00:03:14,000 --> 00:03:19,000
+Just resize widgets like I do here to see all menus and buttons.
+
+42
+00:03:20,000 --> 00:03:26,000
+You can enable creation of dump in a single transaction and include create schema to.
+
+43
+00:03:27,000 --> 00:03:34,000
+After you configure, it's everything you need, just click Start Export button after exports is finished.
+
+44
+00:03:34,000 --> 00:03:40,000
+You can find the results of your exports is a destination that has been configured as a result of the
+
+45
+00:03:40,000 --> 00:03:48,000
+export is nothing more than sequel instructions that create database abuse and insert waiting tables
+
+46
+00:03:48,000 --> 00:03:48,000
+if needed.
+
+47
+00:03:50,000 --> 00:03:53,000
+Now, let's import data into our database.
+
+48
+00:03:53,000 --> 00:04:01,000
+Select Data Import Specify is a project folder with your sequel queries or select radio bottom to specify
+
+49
+00:04:01,000 --> 00:04:02,000
+self-contained file.
+
+50
+00:04:03,000 --> 00:04:08,000
+You can select schema from where to import data or create a new one.
+
+51
+00:04:08,000 --> 00:04:15,000
+This is needed for cases if your sequel instructions that you are going to import don't contain, create
+
+52
+00:04:15,000 --> 00:04:16,000
+schema statement.
+
+53
+00:04:17,000 --> 00:04:20,000
+After that, just click Start Import button, and that's it.
+
+54
+00:04:21,000 --> 00:04:24,000
+They understand how to export and import data.
+
+55
+00:04:24,000 --> 00:04:31,000
+Now, let's now learn how to create users and grant them privileges in management section.
+
+56
+00:04:31,000 --> 00:04:33,000
+I click on user and privileges.
+
+57
+00:04:33,000 --> 00:04:36,000
+Sure, you can see list of user accounts.
+
+58
+00:04:36,000 --> 00:04:39,000
+As you can see, there are some accounts already created.
+
+59
+00:04:40,000 --> 00:04:41,000
+Let's learn What are they?
+
+60
+00:04:42,000 --> 00:04:50,000
+One part of the Mexico installation process is Data Directory initialization durin data directory initialization.
+
+61
+00:04:50,000 --> 00:04:58,000
+My SQL creates user accounts that should be considered to reserve my SQL info schema localhost used
+
+62
+00:04:58,000 --> 00:05:02,000
+as a definer for information schema of use use of them.
+
+63
+00:05:02,000 --> 00:05:09,000
+My SQL Info Schema account avoids problems that occur if a database administrator rename or removes
+
+64
+00:05:09,000 --> 00:05:10,000
+a root account.
+
+65
+00:05:11,000 --> 00:05:18,000
+Use of the My SQL Info Schema account avoids problems that occur if a database administrator names or
+
+66
+00:05:18,000 --> 00:05:20,000
+removes the root account.
+
+67
+00:05:20,000 --> 00:05:26,000
+This account is logged so that it can be used for client connections.
+
+68
+00:05:27,000 --> 00:05:33,000
+My school session localhost used internally by plug ins to access the server.
+
+69
+00:05:33,000 --> 00:05:38,000
+This account is locked so that it can't be used for client connections.
+
+70
+00:05:38,000 --> 00:05:43,000
+My sequels to Sparklehorse used as a defined the forces schema.
+
+71
+00:05:43,000 --> 00:05:46,000
+Objects use of them are sequels.
+
+72
+00:05:46,000 --> 00:05:52,000
+Sequences account avoids problems that occur if a DP renames or removes their account.
+
+73
+00:05:52,000 --> 00:05:57,000
+This account is locked so that it can't be used for client connections.
+
+74
+00:05:58,000 --> 00:06:06,000
+Root localhost used for administrative purposes, this account has old privileges and can perform any
+
+75
+00:06:06,000 --> 00:06:06,000
+operation.
+
+76
+00:06:07,000 --> 00:06:14,000
+Strictly speaking, this account's name is not reserved in the sense that some installations renamed
+
+77
+00:06:14,000 --> 00:06:20,000
+the root account or something else to avoid exposing a highly privileged account was a well known name.
+
+78
+00:06:21,000 --> 00:06:27,000
+But what to do in case we need to create a new user was a separate set of religious Zahra might be different
+
+79
+00:06:27,000 --> 00:06:28,000
+cases.
+
+80
+00:06:28,000 --> 00:06:33,000
+For example, unions separate account for development purposes and you need to restrict some rights
+
+81
+00:06:33,000 --> 00:06:38,000
+for it or you create a database account for your application.
+
+82
+00:06:38,000 --> 00:06:41,000
+And you deliberately want to keep only read rights.
+
+83
+00:06:41,000 --> 00:06:42,000
+Does it make sense?
+
+84
+00:06:43,000 --> 00:06:46,000
+The great new user click Add Account here.
+
+85
+00:06:46,000 --> 00:06:54,000
+We can change the name of new account, select our syndication type for the standard login password
+
+86
+00:06:54,000 --> 00:06:58,000
+densification select standard that's come up was the passwords.
+
+87
+00:06:59,000 --> 00:07:05,000
+You can even configure account limit, for example, amount of queries that can be executed per hour
+
+88
+00:07:06,000 --> 00:07:09,000
+max number of connections concurrent connections.
+
+89
+00:07:10,000 --> 00:07:14,000
+You can check this step to explore more administrative roles.
+
+90
+00:07:14,000 --> 00:07:17,000
+Tap, in my opinion, very important one.
+
+91
+00:07:17,000 --> 00:07:20,000
+You need to grant privileges to your account.
+
+92
+00:07:20,000 --> 00:07:27,000
+In other words, you'll need to specify what new account can and can't do in the database.
+
+93
+00:07:27,000 --> 00:07:33,000
+You can select one or more predefined rules, or you can select privileges manually.
+
+94
+00:07:34,000 --> 00:07:41,000
+It is only up to you and on the last stop here in skimmer privileges, you may said you are just related
+
+95
+00:07:41,000 --> 00:07:42,000
+to schemas.
+
+96
+00:07:42,000 --> 00:07:49,000
+You can add rules for all schemas schemas that margins are provided foreign and concrete schemas.
+
+97
+00:07:50,000 --> 00:07:55,000
+By the way, you can grant and revoke religious even after you create that user account.
+
+98
+00:07:57,000 --> 00:08:03,000
+After you configure it, everything, just click on the apply button and the user will be created.
+
+99
+00:08:03,000 --> 00:08:07,000
+So we created account with select privileges only.
+
+100
+00:08:08,000 --> 00:08:11,000
+Let's now establish new connection using our new credentials.
+
+101
+00:08:12,000 --> 00:08:14,000
+And let's try to drop some table.
+
+102
+00:08:33,000 --> 00:08:40,000
+And you can see that when I tried to drop a table, the command wasn't executed, command was denied
+
+103
+00:08:40,000 --> 00:08:41,000
+for my user.
+
+104
+00:08:42,000 --> 00:08:46,000
+But I still can select any information I need from this schema.
+
+105
+00:08:46,000 --> 00:08:47,000
+Is that clear?
+
+106
+00:08:48,000 --> 00:08:52,000
+Can we understand now how privileges work and how to configure them?
+
+107
+00:08:53,000 --> 00:08:59,000
+The last thing that I'd like quickly to show you is how to track performance of my SQL server in my
+
+108
+00:08:59,000 --> 00:09:00,000
+school workbench.
+
+109
+00:09:00,000 --> 00:09:03,000
+There is a separate section here, as it is called performance.
+
+110
+00:09:04,000 --> 00:09:07,000
+You can open dashboard and track performance in real time.
+
+111
+00:09:08,000 --> 00:09:14,000
+On the dashboards, you can find network status, my SQL status and energy status.
+
+112
+00:09:14,000 --> 00:09:21,000
+When you have queries executed, you will see that this charts will be defined and you can see some
+
+113
+00:09:21,000 --> 00:09:22,000
+measurements here.
+
+114
+00:09:23,000 --> 00:09:27,000
+There are separate widgets that allow you to track status of the storage engine.
+
+115
+00:09:28,000 --> 00:09:31,000
+Most of the metrics and widgets are self-described.
+
+116
+00:09:32,000 --> 00:09:36,000
+And if you follow this course, there is nothing new for you.
+
+117
+00:09:37,000 --> 00:09:43,000
+You should already know what in the day is, what SQL statements are, what select and search create
+
+118
+00:09:43,000 --> 00:09:45,000
+update alternate means.
+
+119
+00:09:46,000 --> 00:09:49,000
+That's all what I wanted to share with you in this lesson.
+
+120
+00:09:50,000 --> 00:09:52,000
+Let's recap what we have learned today.
+
+121
+00:09:53,000 --> 00:09:59,000
+In this lesson, we learned how to make data expert also use, for example, with data inputs.
+
+122
+00:10:00,000 --> 00:10:01,000
+We created new user with you.
+
+123
+00:10:02,000 --> 00:10:08,000
+We can figure global privileges POIs and also contributes schema privileges and advantages.
+
+124
+00:10:08,000 --> 00:10:11,000
+Larson I showed you performance dashboard in my sequel.
+
+125
+00:10:12,000 --> 00:10:12,000
+That's it.
+
+126
+00:10:13,000 --> 00:10:15,000
+Thank you all for your attention.
+
+127
+00:10:15,000 --> 00:10:18,000
+Have a great day and see you in the next lesson.
+

49 - Relational Databases (Advanced)/external-links.txt

@@ -0,0 +1,3 @@
+
+001 Find-folders-with-Views-Triggers-Stored-Procedures-and-Stored-Functions-SQL-query-examples-here
+https://github.com/AndriiPiatakha/learnit_java_core/tree/master/sql_queries/ddl

50 - Databases Database Modelling and Architecture/001 Database Modelling & Design Conceptual, Logical and Physical Data Models_en.srt

@@ -0,0 +1,1160 @@
+1
+00:00:05,000 --> 00:00:11,000
+Hello, Kim, in this lesson, we're going to review very important theoretical concepts of data modeling.
+
+2
+00:00:12,000 --> 00:00:17,000
+This lesson will be useful for everyone, no matter whether you architect or database engineer.
+
+3
+00:00:18,000 --> 00:00:24,000
+We need to learn and understand the basic concepts of data modeling on different levels and different
+
+4
+00:00:24,000 --> 00:00:25,000
+phases of our project.
+
+5
+00:00:26,000 --> 00:00:33,000
+The fundamental understanding of this process has helped me to save a lot of time and avoid a lot of
+
+6
+00:00:33,000 --> 00:00:35,000
+mistakes and rework in the past.
+
+7
+00:00:36,000 --> 00:00:39,000
+That's why I believe it is super important me sharing this with you.
+
+8
+00:00:40,000 --> 00:00:46,000
+We are going to learn such terms as data model, data context, database design, probably explaining
+
+9
+00:00:46,000 --> 00:00:49,000
+why data modeling is super important.
+
+10
+00:00:49,000 --> 00:00:55,000
+And I will provide you with tools and algorithms to ensure efficient process on your project.
+
+11
+00:00:55,000 --> 00:01:02,000
+And after that, we are going to dive into specifics of different data model types and use those with
+
+12
+00:01:02,000 --> 00:01:02,000
+examples.
+
+13
+00:01:03,000 --> 00:01:09,000
+Namely, we are going to discuss conceptual data model, logical data model and physical data model.
+
+14
+00:01:10,000 --> 00:01:15,000
+But then the last thing you are going to have a clear understanding about each type of data model and
+
+15
+00:01:15,000 --> 00:01:16,000
+differences between them.
+
+16
+00:01:17,000 --> 00:01:20,000
+Let's understand first what data model is.
+
+17
+00:01:20,000 --> 00:01:28,000
+A data model is an abstract model that organizes elements of data and standardize how they relate to
+
+18
+00:01:28,000 --> 00:01:32,000
+one another and to the properties of the real world with this.
+
+19
+00:01:33,000 --> 00:01:40,000
+For example, a data model may specify that the data elements representing a car be composed of a number
+
+20
+00:01:40,000 --> 00:01:49,000
+of elements, which in turn represent a color and the size of the car and define its own term data model
+
+21
+00:01:49,000 --> 00:01:54,000
+can refer to two distinct but closely related concepts.
+
+22
+00:01:54,000 --> 00:02:01,000
+Sometimes it refers to an absolute formalization of the objects and relationships found, in particular
+
+23
+00:02:01,000 --> 00:02:03,000
+application domain.
+
+24
+00:02:03,000 --> 00:02:11,000
+For example, the customers products and orders found in manufacturing and analyzation, and other times
+
+25
+00:02:11,000 --> 00:02:16,000
+it refers to a set of concepts used in defining such formalization.
+
+26
+00:02:17,000 --> 00:02:22,000
+For example, concepts such as entities, attributes, relations or tables.
+
+27
+00:02:23,000 --> 00:02:29,000
+So is a data model of a banking application may be defined using the entity.
+
+28
+00:02:29,000 --> 00:02:35,000
+Relationship data model and data model explicitly determines the structure of data.
+
+29
+00:02:36,000 --> 00:02:40,000
+The next item is related to the previous one database model.
+
+30
+00:02:41,000 --> 00:02:49,000
+What is a database model that the base model is a type of data model that determines zoological structure
+
+31
+00:02:49,000 --> 00:02:50,000
+of a database.
+
+32
+00:02:50,000 --> 00:02:57,000
+It fundamentally determines in which manner data can be stored, organized and manipulated.
+
+33
+00:02:57,000 --> 00:03:04,000
+The most popular example of database model is a relational model, which uses a table based format.
+
+34
+00:03:05,000 --> 00:03:12,000
+Database model refers to the logical structure, representation all the out of the database and how
+
+35
+00:03:12,000 --> 00:03:17,000
+the data will be stored, managed and processed within it.
+
+36
+00:03:17,000 --> 00:03:26,000
+It helps in designing a database and serves as a blueprint for application developers and database administrators
+
+37
+00:03:26,000 --> 00:03:27,000
+in creating a database.
+
+38
+00:03:28,000 --> 00:03:36,000
+You are more or less already familiar with relational data model, so relational data model is an approach
+
+39
+00:03:36,000 --> 00:03:43,000
+to managing data using a structure and language consistent with logic where all data is represented
+
+40
+00:03:43,000 --> 00:03:51,000
+in terms of tables grouped into relations, and we learn all the different types of relations in a separate
+
+41
+00:03:51,000 --> 00:03:51,000
+lesson.
+
+42
+00:03:52,000 --> 00:03:55,000
+There are three main groups of data models.
+
+43
+00:03:55,000 --> 00:03:59,000
+They are logical, conceptual and physical.
+
+44
+00:04:00,000 --> 00:04:04,000
+In this lesson, we are going to go all of them and understand the difference between them.
+
+45
+00:04:05,000 --> 00:04:11,000
+But before we even try to understand the difference between different groups of data model, let's make
+
+46
+00:04:11,000 --> 00:04:18,000
+sure that we all understand the importance of data modeling and try to understand motivations that stands
+
+47
+00:04:18,000 --> 00:04:19,000
+behind this lesson.
+
+48
+00:04:20,000 --> 00:04:29,000
+Data modeling is a process of creating a visual representation of a whole information system or parts
+
+49
+00:04:29,000 --> 00:04:33,000
+of it to communicate connections between data points and structures.
+
+50
+00:04:34,000 --> 00:04:39,000
+The goal is to illustrate the types of data used and stored within the system.
+
+51
+00:04:39,000 --> 00:04:42,000
+The relationships and ones these data types.
+
+52
+00:04:42,000 --> 00:04:48,000
+The ways that data can be grouped and organized, and its formats and attributes.
+
+53
+00:04:49,000 --> 00:04:50,000
+Why we need data modeling.
+
+54
+00:04:51,000 --> 00:04:52,000
+Can we live without it at all?
+
+55
+00:04:53,000 --> 00:04:55,000
+Well, to answer objectively.
+
+56
+00:04:56,000 --> 00:05:02,000
+But in my opinion, we can't leave without data model unions, the development of our app.
+
+57
+00:05:03,000 --> 00:05:08,000
+It is only a matter of how you will come up with a data model for your app, but you will spend some
+
+58
+00:05:08,000 --> 00:05:13,000
+time on data monitoring for sure, and it will be done in one or another way.
+
+59
+00:05:14,000 --> 00:05:20,000
+And what I like to explain this lesson is to give you standardized tools and approaches for data modeling,
+
+60
+00:05:21,000 --> 00:05:25,000
+because creating proper data models for all app, it is super important task.
+
+61
+00:05:26,000 --> 00:05:32,000
+And sometimes it is hard just to create a few tables straight away and start using specific data structures
+
+62
+00:05:32,000 --> 00:05:34,000
+and build your codes around.
+
+63
+00:05:34,000 --> 00:05:36,000
+Identify dependencies.
+
+64
+00:05:36,000 --> 00:05:41,000
+If you still can't understand how it is important, think about it.
+
+65
+00:05:41,000 --> 00:05:48,000
+Also from different than user development of application is performed by multiple developers.
+
+66
+00:05:48,000 --> 00:05:55,000
+It can be to engineers in case this is early stages of a startup and it can be significantly more engineers
+
+67
+00:05:55,000 --> 00:05:59,000
+if you already have proof of concept and the boat to start feature development.
+
+68
+00:06:00,000 --> 00:06:08,000
+Now, imagine that lack of database design and pure data modeling because the or one or even multiple
+
+69
+00:06:08,000 --> 00:06:09,000
+features.
+
+70
+00:06:09,000 --> 00:06:12,000
+How much money will you spend on salary of engineers?
+
+71
+00:06:12,000 --> 00:06:16,000
+The change also caught is it was built around this data model.
+
+72
+00:06:16,000 --> 00:06:23,000
+Definitely desert techniques of green architecture and introduction of abstraction layer in your app
+
+73
+00:06:23,000 --> 00:06:26,000
+that minimize rewriting of all persistence layer.
+
+74
+00:06:27,000 --> 00:06:35,000
+So definitely, this won't be like dramatic impact, but still sometimes changes in business model mapping
+
+75
+00:06:35,000 --> 00:06:44,000
+may impact business logic and the way how you interact with data inside your app and how you practice
+
+76
+00:06:44,000 --> 00:06:44,000
+it.
+
+77
+00:06:44,000 --> 00:06:50,000
+The ability to correct it and devise a business and adjust ends the way we want it to models.
+
+78
+00:06:50,000 --> 00:06:54,000
+Those relationships is pivotal to good information quality.
+
+79
+00:06:55,000 --> 00:07:02,000
+Most teams and other musicians opt for physical modeling and great application specific schemas that
+
+80
+00:07:02,000 --> 00:07:04,000
+often lack the high level vision.
+
+81
+00:07:04,000 --> 00:07:08,000
+So how is the business really needs to utilize its data?
+
+82
+00:07:09,000 --> 00:07:12,000
+Also, there is one more related term.
+
+83
+00:07:12,000 --> 00:07:13,000
+It is database design.
+
+84
+00:07:14,000 --> 00:07:14,000
+What is it?
+
+85
+00:07:15,000 --> 00:07:17,000
+Database design is organizational data.
+
+86
+00:07:17,000 --> 00:07:25,000
+According to database model, the designer determines what data must be stored and how the data elements
+
+87
+00:07:25,000 --> 00:07:26,000
+interrelate.
+
+88
+00:07:26,000 --> 00:07:29,000
+Database management system manages the data accordingly.
+
+89
+00:07:30,000 --> 00:07:36,000
+Database design involves classifying data and identifying interrelationships.
+
+90
+00:07:36,000 --> 00:07:41,000
+This surgical representation of the data is called an ontology.
+
+91
+00:07:41,000 --> 00:07:49,000
+The ontology is a theory behind the databases design in order to perform data more an inefficient way.
+
+92
+00:07:49,000 --> 00:07:52,000
+We need to have a clear understanding of data context.
+
+93
+00:07:53,000 --> 00:07:59,000
+You can treat data as a puzzle where a puzzle piece is a data entity.
+
+94
+00:07:59,000 --> 00:08:07,000
+If you would like me to be not so specific in concrete terms but define an abstraction instead of data
+
+95
+00:08:07,000 --> 00:08:09,000
+entity, we can use any other terms.
+
+96
+00:08:10,000 --> 00:08:18,000
+So as a piece of Basel, you can use any concept or important thing for business about which we want
+
+97
+00:08:18,000 --> 00:08:27,000
+to collect data and in order to get it pieces and in order to get the pieces to fit together, you need
+
+98
+00:08:27,000 --> 00:08:33,000
+to understand the proper relationship of the piece in question to the other puzzle pieces.
+
+99
+00:08:34,000 --> 00:08:41,000
+The conceptual data model is a picture on the puzzle books that provides a vision of what Information
+
+100
+00:08:41,000 --> 00:08:47,000
+Basel should look like at the end of the day, regardless of whether your solution is a data warehouse,
+
+101
+00:08:47,000 --> 00:08:51,000
+ERP mustard that the management or anything else.
+
+102
+00:08:52,000 --> 00:09:00,000
+Now, let's hear what the conceptual data model is, that conceptual data model is a diagram identifies
+
+103
+00:09:00,000 --> 00:09:07,000
+the business concepts well, like we usually call them, and that is also this type of data model identifies
+
+104
+00:09:07,000 --> 00:09:14,000
+the relationships between these concepts in order to gain, reflect and document understanding of the
+
+105
+00:09:14,000 --> 00:09:16,000
+organization's business from a data perspective.
+
+106
+00:09:17,000 --> 00:09:20,000
+It shows how the business world sees information.
+
+107
+00:09:21,000 --> 00:09:27,000
+It suppresses non-critical details in order to emphasize business rules and user objects.
+
+108
+00:09:28,000 --> 00:09:35,000
+It typically includes on the significant entities which have business meaning, along with their relationships
+
+109
+00:09:35,000 --> 00:09:39,000
+and conceptual data model usually takes the form of an entity.
+
+110
+00:09:39,000 --> 00:09:47,000
+Relationship diagram or object role model is a conceptual data model typically does not contain attributes
+
+111
+00:09:48,000 --> 00:09:55,000
+or if it does on the significant attributes it is important to mention is that the conceptual data model
+
+112
+00:09:55,000 --> 00:09:59,000
+is technology and application independent.
+
+113
+00:09:59,000 --> 00:10:06,000
+The conceptual data model should reflect relationships from a historical longitudinal perspective.
+
+114
+00:10:07,000 --> 00:10:13,000
+For example, a relationship between a store and employee may usually be considered as one too many,
+
+115
+00:10:14,000 --> 00:10:20,000
+but when viewed from a historical perspective, perhaps zero relationships may actually be managed.
+
+116
+00:10:20,000 --> 00:10:28,000
+Many whether the employee begins work at another store, why conceptual data model is important and
+
+117
+00:10:28,000 --> 00:10:34,000
+what issues you may encounter in case you skip trace of conceptual datum or design.
+
+118
+00:10:35,000 --> 00:10:42,000
+You may be constantly stumbling through zealots conceptual data model, but you won't see the big picture.
+
+119
+00:10:43,000 --> 00:10:49,000
+It is hard to identify and understand all possible relationships that are required and miss important
+
+120
+00:10:49,000 --> 00:10:56,000
+seems when you are down in the details of the development and new system from scratch, especially when
+
+121
+00:10:56,000 --> 00:10:59,000
+you work on some complex enterprise solution.
+
+122
+00:10:59,000 --> 00:11:08,000
+The three basic tenets of conceptual data model are entity, a real world, single attribute characteristics
+
+123
+00:11:08,000 --> 00:11:15,000
+or properties of an entity, relationship dependency or association between entities.
+
+124
+00:11:16,000 --> 00:11:20,000
+Conceptual data model, example, customer and product are two entities.
+
+125
+00:11:21,000 --> 00:11:28,000
+Customer number and name attributes of the customer, entity, product, name and price are attributes
+
+126
+00:11:28,000 --> 00:11:29,000
+of product entity.
+
+127
+00:11:29,000 --> 00:11:32,000
+Sale is a relationship between the customer and product.
+
+128
+00:11:33,000 --> 00:11:40,000
+As you can see, this is not like super detailed vision of data model, and therefore this is not ready
+
+129
+00:11:40,000 --> 00:11:46,000
+to use database that is built with the specifics of database management system and logical data model
+
+130
+00:11:46,000 --> 00:11:49,000
+is a data model of a specific problem.
+
+131
+00:11:49,000 --> 00:11:55,000
+The main expressed independently of a particular database management product or storage technology,
+
+132
+00:11:56,000 --> 00:12:03,000
+but nevertheless logical data model is visualized and described in terms of known data structures.
+
+133
+00:12:03,000 --> 00:12:10,000
+For example, logical data model may be described as relational tables and columns, object oriented
+
+134
+00:12:10,000 --> 00:12:12,000
+colossus or similar tax.
+
+135
+00:12:13,000 --> 00:12:18,000
+Sometimes in the literature, you may find that it is referred as logical schema.
+
+136
+00:12:19,000 --> 00:12:26,000
+Logical database design describes the data without any details of how exactly this data will be physically
+
+137
+00:12:26,000 --> 00:12:27,000
+implemented.
+
+138
+00:12:27,000 --> 00:12:35,000
+This database and logical data models It is worse to highlight the next once hierarchical database model.
+
+139
+00:12:36,000 --> 00:12:39,000
+It is the oldest form of database model.
+
+140
+00:12:39,000 --> 00:12:43,000
+It was developed by IBM for Information Management System.
+
+141
+00:12:44,000 --> 00:12:47,000
+It is a set of organized data into structure.
+
+142
+00:12:48,000 --> 00:12:53,000
+DB Record is a three and system of many groups called segments.
+
+143
+00:12:54,000 --> 00:12:56,000
+It uses one to many relationships.
+
+144
+00:12:56,000 --> 00:12:59,000
+The data access is also predictable.
+
+145
+00:13:00,000 --> 00:13:01,000
+Network model.
+
+146
+00:13:02,000 --> 00:13:08,000
+It is a database model conceived as a flexible way of representing objects and their relationships.
+
+147
+00:13:08,000 --> 00:13:17,000
+It's distinguishing feature is that the schema used as a graph in which object types and loads and the
+
+148
+00:13:17,000 --> 00:13:19,000
+relationship types are arcs.
+
+149
+00:13:20,000 --> 00:13:26,000
+It is not restricted to being a hierarchy, a lattice relational model.
+
+150
+00:13:27,000 --> 00:13:33,000
+This is probably one of the most popular data models nowadays, where all data is represented in terms
+
+151
+00:13:33,000 --> 00:13:40,000
+of doubles grouped into relations, and that your relationship model just collapse into the later things
+
+152
+00:13:40,000 --> 00:13:41,000
+of interest.
+
+153
+00:13:42,000 --> 00:13:49,000
+The specific domain of knowledge and basic our model is composed of an entity, Typekit, which classifies
+
+154
+00:13:49,000 --> 00:13:55,000
+as things of interest and specifies relationships that can exist between entities.
+
+155
+00:13:55,000 --> 00:13:57,000
+You can see that on diagram.
+
+156
+00:13:57,000 --> 00:14:04,000
+It is super easy to understand relationships between entities because of reasonable way of depicting
+
+157
+00:14:04,000 --> 00:14:06,000
+all connections and their types.
+
+158
+00:14:07,000 --> 00:14:08,000
+Object model.
+
+159
+00:14:08,000 --> 00:14:15,000
+It is a database management system in which information is represented in the form of object as used
+
+160
+00:14:15,000 --> 00:14:17,000
+in object oriented programming.
+
+161
+00:14:17,000 --> 00:14:22,000
+Object databases are different from relational database, which are table oriented.
+
+162
+00:14:23,000 --> 00:14:26,000
+Object or relational database is a hybrid of both approaches.
+
+163
+00:14:27,000 --> 00:14:35,000
+Documents model, this is data storage system designed for storing, retrieving and managing documents
+
+164
+00:14:35,000 --> 00:14:39,000
+oriented information, also known as semi-structured data.
+
+165
+00:14:39,000 --> 00:14:46,000
+And if you remember our lesson about overview of different database management systems Xeni should remember
+
+166
+00:14:46,000 --> 00:14:53,000
+is a document model is probably one of the main data models that is used in the design of NoSQL database.
+
+167
+00:14:54,000 --> 00:14:56,000
+Entity attributes value model.
+
+168
+00:14:56,000 --> 00:15:03,000
+It is a data model to encode in a space efficient manner, and that is where a number of attributes,
+
+169
+00:15:04,000 --> 00:15:11,000
+properties parameters can be used to describe them is potentially vast, but the numbers it will actually
+
+170
+00:15:11,000 --> 00:15:14,000
+apply to even entity is relatively modest.
+
+171
+00:15:15,000 --> 00:15:22,000
+Such entities correspond to the mathematical notion of sparse markets star schema.
+
+172
+00:15:23,000 --> 00:15:30,000
+It is the simplest style of data more schema and is the approach most widely used to develop data warehouses
+
+173
+00:15:30,000 --> 00:15:32,000
+and dimensional data models.
+
+174
+00:15:33,000 --> 00:15:40,000
+Logical data model is as opposed to a conceptual data model, which describes the semantics of an organization
+
+175
+00:15:40,000 --> 00:15:42,000
+without reference to technology.
+
+176
+00:15:43,000 --> 00:15:46,000
+Logical models are often that romantic in nature.
+
+177
+00:15:47,000 --> 00:15:48,000
+When are they used?
+
+178
+00:15:49,000 --> 00:15:52,000
+Usually, they're most used in business processes.
+
+179
+00:15:53,000 --> 00:16:00,000
+Once validated and approved, the logical data model becomes the basis of a physical data model and
+
+180
+00:16:00,000 --> 00:16:02,000
+for the design of a database.
+
+181
+00:16:02,000 --> 00:16:10,000
+The term logical data model is sometimes used as a synonym of the mean model or as an alternative to
+
+182
+00:16:10,000 --> 00:16:11,000
+the mean model.
+
+183
+00:16:12,000 --> 00:16:19,000
+While the two concepts are closely related and have overlapping goals and the main model is more focused
+
+184
+00:16:19,000 --> 00:16:21,000
+on capturing the concepts, it a problem.
+
+185
+00:16:21,000 --> 00:16:30,000
+The main residence structure of the data associated with the main zoological data model is used to define
+
+186
+00:16:30,000 --> 00:16:35,000
+the structure of data elements and to set relationships between them.
+
+187
+00:16:36,000 --> 00:16:41,000
+Zoological data model adds further information to the conceptual data model elements.
+
+188
+00:16:41,000 --> 00:16:48,000
+The advantage of using a logical data model is to provide the foundation, the forms, the base for
+
+189
+00:16:48,000 --> 00:16:49,000
+the physical model.
+
+190
+00:16:50,000 --> 00:16:53,000
+However, the model structure remains generic.
+
+191
+00:16:54,000 --> 00:17:00,000
+The next things that we are going to learn today is to learn more about the group of physical data models.
+
+192
+00:17:01,000 --> 00:17:08,000
+Let's start from the definition the physical data model is a representation of a data design as implemented
+
+193
+00:17:08,000 --> 00:17:12,000
+or intended to be implemented in a database management system.
+
+194
+00:17:13,000 --> 00:17:20,000
+The feel right is a difference between conceptual and logical data models in the lifecycle of a project.
+
+195
+00:17:20,000 --> 00:17:24,000
+It typically derives from a logical data model.
+
+196
+00:17:24,000 --> 00:17:29,000
+So it may be reverse engineered from a given database implementation.
+
+197
+00:17:29,000 --> 00:17:36,000
+A complete physical data model will include all the database artifacts required, the great relationships
+
+198
+00:17:36,000 --> 00:17:45,000
+between tables or to achieve performance goals such as indexes considering definitions, Lincoln tables,
+
+199
+00:17:45,000 --> 00:17:47,000
+partition tables or clusters.
+
+200
+00:17:48,000 --> 00:17:53,000
+Physical database design represents how the actual database is built in.
+
+201
+00:17:53,000 --> 00:17:59,000
+The first lesson of my course about databases you learned the most popular database management systems.
+
+202
+00:18:00,000 --> 00:18:05,000
+Please refer to that lesson if you want to check specific names and database management systems.
+
+203
+00:18:05,000 --> 00:18:14,000
+There are two main physical data models Inverted Index, and that file inverted index that is also referred
+
+204
+00:18:14,000 --> 00:18:23,000
+to as a custom file or inverted file, is a database in storing and mapping some content, such as words
+
+205
+00:18:23,000 --> 00:18:30,000
+or numbers, to its location, in a table or in a document, or in a set of documents.
+
+206
+00:18:30,000 --> 00:18:35,000
+In this course, you also can find less about indexes and how to book with them.
+
+207
+00:18:36,000 --> 00:18:41,000
+In that lesson, we discuss specifics of interaction with index from its creation until its removal.
+
+208
+00:18:42,000 --> 00:18:50,000
+The purpose of an inverted index is to allow fast, full text searches at the cost of increased processing.
+
+209
+00:18:50,000 --> 00:18:54,000
+When a document would just in Utah, Apple is added to the database.
+
+210
+00:18:54,000 --> 00:19:01,000
+So basically the performance of reading and searching data will be better and will be executed faster.
+
+211
+00:19:02,000 --> 00:19:07,000
+But on the other hand, operations of insertion will take more time.
+
+212
+00:19:07,000 --> 00:19:15,000
+That is because after adding additional rule, autoplay indexes needed to be recalculated to stay sorted
+
+213
+00:19:15,000 --> 00:19:23,000
+and ensure logarithmic connotation for extraction operations, zingers at file may be a database file
+
+214
+00:19:23,000 --> 00:19:25,000
+itself rather than its index.
+
+215
+00:19:26,000 --> 00:19:32,000
+It is the most popular data structure used in document retrieval systems used on the large scale.
+
+216
+00:19:32,000 --> 00:19:35,000
+For example, in search engines.
+
+217
+00:19:35,000 --> 00:19:42,000
+On the other hand, a flat file database is a database stored in the file called a flat file.
+
+218
+00:19:43,000 --> 00:19:50,000
+Records follow a uniform format, and there are no structure for indexing or recognizing relationships
+
+219
+00:19:50,000 --> 00:19:51,000
+between records.
+
+220
+00:19:51,000 --> 00:19:57,000
+This file is simple a flat file can be a plain text file or a binary file.
+
+221
+00:19:58,000 --> 00:20:06,000
+Relationships can be inferred from the data in the database, but the database format itself doesn't
+
+222
+00:20:06,000 --> 00:20:08,000
+make those relationships explicit.
+
+223
+00:20:08,000 --> 00:20:16,000
+The term has generally implied a small database, but very large that the basis can also be flat.
+
+224
+00:20:16,000 --> 00:20:23,000
+If you want an example of a flat file database, you can imagine Linnaeus thought of the sequel data.
+
+225
+00:20:24,000 --> 00:20:29,000
+A physical dating model describes that the base specific implementation of the data model.
+
+226
+00:20:29,000 --> 00:20:34,000
+It offers database abstraction and helps generate the schema.
+
+227
+00:20:34,000 --> 00:20:41,000
+The main difference between logical database design and physical database design is that logical database
+
+228
+00:20:41,000 --> 00:20:45,000
+design helps to define the data elements and their relationships.
+
+229
+00:20:46,000 --> 00:20:52,000
+But physical database design helps to design the actual database based on the requirements gathered
+
+230
+00:20:52,000 --> 00:20:56,000
+doing the logical data design and conceptual data design.
+
+231
+00:20:57,000 --> 00:21:04,000
+We learned what conceptual data model, logical data model and physical data model is to help you understand
+
+232
+00:21:04,000 --> 00:21:06,000
+better the difference between all of these.
+
+233
+00:21:07,000 --> 00:21:09,000
+I want to present use of current slide.
+
+234
+00:21:10,000 --> 00:21:16,000
+So let's recap in one sentence about each type of data model's conceptual data model.
+
+235
+00:21:17,000 --> 00:21:20,000
+This data model defines what the system contains.
+
+236
+00:21:21,000 --> 00:21:26,000
+This model is typically created by business stakeholders and data architects.
+
+237
+00:21:26,000 --> 00:21:32,000
+The purpose is to organize, scope and define business concepts and rules.
+
+238
+00:21:32,000 --> 00:21:39,000
+Logical data model defines how the system should be implemented regardless of the database management
+
+239
+00:21:39,000 --> 00:21:39,000
+system.
+
+240
+00:21:40,000 --> 00:21:45,000
+This model is typically created by data architects and business analysts.
+
+241
+00:21:45,000 --> 00:21:50,000
+The purpose is to develop a technical map of rules and data structures.
+
+242
+00:21:51,000 --> 00:21:58,000
+Physical data model This data model describes how the system will be implemented using a specific database
+
+243
+00:21:58,000 --> 00:21:59,000
+management system.
+
+244
+00:22:00,000 --> 00:22:04,000
+This model is typically created by database architects and developers.
+
+245
+00:22:05,000 --> 00:22:08,000
+The purpose is actual implementation of the database.
+
+246
+00:22:09,000 --> 00:22:15,000
+A conceptual data model identifies the highest level relationships between the different, and that
+
+247
+00:22:15,000 --> 00:22:22,000
+these features of conceptual data model include the important entities and the relationships among them.
+
+248
+00:22:23,000 --> 00:22:24,000
+No attribute is specified.
+
+249
+00:22:24,000 --> 00:22:26,000
+No primary key is specified.
+
+250
+00:22:27,000 --> 00:22:35,000
+A logical data model describes the data in as much detail as possible without regard to how they will
+
+251
+00:22:35,000 --> 00:22:37,000
+be physically implemented in the database.
+
+252
+00:22:37,000 --> 00:22:44,000
+Features of logical data model include all entities and relationships, and also all attributes for
+
+253
+00:22:44,000 --> 00:22:50,000
+each entity are specified is a primary key for each entity is specified.
+
+254
+00:22:50,000 --> 00:22:55,000
+Foreign keys incident defines the relationship between different entities.
+
+255
+00:22:55,000 --> 00:22:59,000
+A specified normalization occurs at this level.
+
+256
+00:23:00,000 --> 00:23:06,000
+The steps for design and the logical data model are as follows Specified primary keys for all entities
+
+257
+00:23:07,000 --> 00:23:09,000
+find the relationships between different entities.
+
+258
+00:23:10,000 --> 00:23:12,000
+Find all attributes for each entity.
+
+259
+00:23:13,000 --> 00:23:17,000
+Resolve many to many relationships normalization.
+
+260
+00:23:17,000 --> 00:23:20,000
+You can learn more about normalization from other lessons.
+
+261
+00:23:20,000 --> 00:23:26,000
+Of course, this is also a very important topic, and I dedicated a lot of time and attention to it.
+
+262
+00:23:27,000 --> 00:23:34,000
+Physical data model represents how the model will be built into database, a physical database model
+
+263
+00:23:34,000 --> 00:23:41,000
+shows all table structures, including column name, column data, type, column constraints, primary
+
+264
+00:23:41,000 --> 00:23:45,000
+key, foreign key and relationships between tables.
+
+265
+00:23:46,000 --> 00:23:51,000
+Features of a physical data model include specification of all tables and columns.
+
+266
+00:23:52,000 --> 00:23:55,000
+Foreign keys are used to identify relationships between tables.
+
+267
+00:23:56,000 --> 00:24:00,000
+The normalization may occur based on user requirements.
+
+268
+00:24:00,000 --> 00:24:06,000
+If you don't know what the normalization is, please refer to the lesson about normalization and normal
+
+269
+00:24:06,000 --> 00:24:09,000
+forms in scope of that lesson.
+
+270
+00:24:09,000 --> 00:24:12,000
+I also described what normalization is.
+
+271
+00:24:13,000 --> 00:24:18,000
+Physical considerations may cause the physical data model to be quite different from the logical data
+
+272
+00:24:18,000 --> 00:24:19,000
+model.
+
+273
+00:24:19,000 --> 00:24:24,000
+Physical data model will be different for different database management systems.
+
+274
+00:24:24,000 --> 00:24:32,000
+For example, data type for a call made the difference between Oracle and DB two, and also there might
+
+275
+00:24:32,000 --> 00:24:33,000
+be other differences.
+
+276
+00:24:33,000 --> 00:24:41,000
+The steps for physical data modal design are as follows Converged entities into tables convert relationships
+
+277
+00:24:41,000 --> 00:24:45,000
+into foreign keys, convert attributes into columns.
+
+278
+00:24:46,000 --> 00:24:50,000
+Modifies the physical data model based on physical constraints.
+
+279
+00:24:50,000 --> 00:24:50,000
+Mark ones.
+
+280
+00:24:51,000 --> 00:24:53,000
+That's all what I wanted to share with you today.
+
+281
+00:24:54,000 --> 00:24:57,000
+You learned a lot of important and interesting things today.
+
+282
+00:24:58,000 --> 00:25:01,000
+Let's review what we have learned in this lesson.
+
+283
+00:25:01,000 --> 00:25:06,000
+We learned what data model and that the base model is what discussed.
+
+284
+00:25:06,000 --> 00:25:08,000
+What database design is.
+
+285
+00:25:08,000 --> 00:25:12,000
+Also, we discussed and understood the importance of data modeling process.
+
+286
+00:25:13,000 --> 00:25:15,000
+After this lesson, you know what?
+
+287
+00:25:15,000 --> 00:25:20,000
+Data context is relative used and learned three main groups of data models.
+
+288
+00:25:21,000 --> 00:25:25,000
+They are conceptual, logical and physical data models.
+
+289
+00:25:26,000 --> 00:25:28,000
+Thanks a lot for your attention.
+
+290
+00:25:28,000 --> 00:25:31,000
+Have a great day and see you in the next lesson.
+

51 - ===== SQL Homework Online Shop =====/001 Homework-with-links-to-solution.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://docs.google.com/document/d/10Wz-j_aerkD-Z9A4reYYp9nPS69NF19w71Fq6YU-M50/edit?usp=sharing

51 - ===== SQL Homework Online Shop =====/001 SQL Homework Task and Solution Review_en.srt

@@ -0,0 +1,400 @@
+1
+00:00:06,000 --> 00:00:06,000
+Hello, Jim.
+
+2
+00:00:07,000 --> 00:00:11,000
+In this video, we're going to review with you your home tasks, the task that I'm going to share with
+
+3
+00:00:11,000 --> 00:00:15,000
+your supposed to help you learn and understand school topic matter.
+
+4
+00:00:16,000 --> 00:00:22,000
+If you are students of my Java from zero, the first job course, you should already know that you're
+
+5
+00:00:22,000 --> 00:00:23,000
+in the course.
+
+6
+00:00:23,000 --> 00:00:26,000
+We work on creation of our own online shop.
+
+7
+00:00:26,000 --> 00:00:31,000
+We also need to have a database to support main operations in our online shop.
+
+8
+00:00:32,000 --> 00:00:38,000
+That's why in today's homework, we are going to have ecommerce terminology anyway.
+
+9
+00:00:38,000 --> 00:00:43,000
+I believe this will be interesting for you because the whole tasks that I would ask you to implement
+
+10
+00:00:43,000 --> 00:00:46,000
+are closely related to real life examples.
+
+11
+00:00:47,000 --> 00:00:52,000
+And the first things that you need to do is to make sure that you have all necessary tables to execute
+
+12
+00:00:52,000 --> 00:00:59,000
+queries from your home, tasks to help you create all necessary tables, foster and populate data.
+
+13
+00:00:59,000 --> 00:01:04,000
+I prepared a special script for you that you just need to execute in your database.
+
+14
+00:01:05,000 --> 00:01:10,000
+Just open this link, copy the script and execute it in your database.
+
+15
+00:01:11,000 --> 00:01:17,000
+Once this script will be executed, you will notice that five tables created in your database take your
+
+16
+00:01:17,000 --> 00:01:19,000
+time to explore those tables.
+
+17
+00:01:19,000 --> 00:01:21,000
+This structure and they things out.
+
+18
+00:01:22,000 --> 00:01:25,000
+Pay attention to the type of the relationships between different entities.
+
+19
+00:01:26,000 --> 00:01:31,000
+Once you have all necessary tables and data in it, we are ready to proceed with home tasks.
+
+20
+00:01:32,000 --> 00:01:38,000
+The first task is to select distinct emails of users who made at least one purchase.
+
+21
+00:01:39,000 --> 00:01:41,000
+Basically, nuts in this complex here.
+
+22
+00:01:42,000 --> 00:01:47,000
+This query was required to create joint query to two tables, purchases and user.
+
+23
+00:01:48,000 --> 00:01:53,000
+The second task would be to create SQL queries that will select product names and purchase ideas for
+
+24
+00:01:53,000 --> 00:01:54,000
+each purchase.
+
+25
+00:01:55,000 --> 00:02:00,000
+Set tasks to create sequel statement to select credit card and product name.
+
+26
+00:02:01,000 --> 00:02:06,000
+You should select credit cards as it was used for purchase of this specific product.
+
+27
+00:02:07,000 --> 00:02:14,000
+One more task is to select last name of user and total amount of purchases made by this user.
+
+28
+00:02:14,000 --> 00:02:16,000
+This is going to be a really interesting one.
+
+29
+00:02:17,000 --> 00:02:22,000
+Select less name of user and total amount of purchases made by this user.
+
+30
+00:02:22,000 --> 00:02:26,000
+Only for users who make two or more purchases.
+
+31
+00:02:27,000 --> 00:02:33,000
+And last but not least, task is to select total amount of money user already spent in our store.
+
+32
+00:02:34,000 --> 00:02:41,000
+As you can see, I tried to come up with real life business cases by implementing this squarish.
+
+33
+00:02:41,000 --> 00:02:44,000
+You will be able to practice your knowledge in aggregate functions.
+
+34
+00:02:44,000 --> 00:02:49,000
+Junqueras groupings are results, applying different conditions and so on.
+
+35
+00:02:50,000 --> 00:02:52,000
+Don't hurry up to check my solution.
+
+36
+00:02:53,000 --> 00:02:56,000
+Try to take your time and come up with your solution first.
+
+37
+00:02:57,000 --> 00:03:04,000
+Try to create queries by analogy because during the course, we already created similar queries in some
+
+38
+00:03:04,000 --> 00:03:04,000
+tasks.
+
+39
+00:03:04,000 --> 00:03:11,000
+From the least, you may need to have multiple joints, press, pause, and once you are done with your
+
+40
+00:03:11,000 --> 00:03:13,000
+solution, resumes the video.
+
+41
+00:03:13,000 --> 00:03:18,000
+And let's compare my and your solution in the first task.
+
+42
+00:03:18,000 --> 00:03:23,000
+I use distinct keywords to extract only distinct user emails.
+
+43
+00:03:24,000 --> 00:03:32,000
+I use joint statement to make joint query on purchase table to make sure that I extract only users that
+
+44
+00:03:32,000 --> 00:03:34,000
+have associated records in purchased table.
+
+45
+00:03:35,000 --> 00:03:40,000
+I use foreign key in purchased table to map records between two tables.
+
+46
+00:03:41,000 --> 00:03:43,000
+Here we have one too many relationships.
+
+47
+00:03:44,000 --> 00:03:50,000
+That's why there is no need in this table, and we can easily implement this relationship with the help
+
+48
+00:03:50,000 --> 00:03:52,000
+of foreign key and purchase table.
+
+49
+00:03:52,000 --> 00:03:53,000
+Does it make sense?
+
+50
+00:03:54,000 --> 00:03:56,000
+Is everything clear so far?
+
+51
+00:03:57,000 --> 00:04:03,000
+And by the way, team, as always, in case you have any questions, please do not hesitate to put your
+
+52
+00:04:03,000 --> 00:04:07,000
+questions and comments below this video, and I will be happy to answer those.
+
+53
+00:04:08,000 --> 00:04:15,000
+Second task is almost similar to the first one in terms that we create joint statements two two tables
+
+54
+00:04:15,000 --> 00:04:16,000
+only.
+
+55
+00:04:16,000 --> 00:04:24,000
+We need to extract information about product and we can extracted from product table and to verify in
+
+56
+00:04:24,000 --> 00:04:26,000
+which purchase this product was purchased.
+
+57
+00:04:27,000 --> 00:04:30,000
+We need to check this in purchased product table.
+
+58
+00:04:31,000 --> 00:04:34,000
+In the search task, we need to create multiple joints.
+
+59
+00:04:34,000 --> 00:04:35,000
+Why?
+
+60
+00:04:35,000 --> 00:04:42,000
+Because we need to extract credit card value that is stored in user table and product names at the storage
+
+61
+00:04:42,000 --> 00:04:43,000
+product table.
+
+62
+00:04:43,000 --> 00:04:49,000
+But to identify which shoes are bought, which products, we need to query purchase table.
+
+63
+00:04:49,000 --> 00:04:53,000
+Because some purchase table, there is an info about users purchases.
+
+64
+00:04:54,000 --> 00:05:00,000
+But to understand which product has been purchased in scope of which purchase, we need to query purchase
+
+65
+00:05:00,000 --> 00:05:06,000
+product table because there is many, too many relationships between product and purchase.
+
+66
+00:05:07,000 --> 00:05:10,000
+Each purchase may consist of multiple products, correct?
+
+67
+00:05:11,000 --> 00:05:17,000
+During the one session, I can buy a laptop and separate keyboards, for example, and each product
+
+68
+00:05:17,000 --> 00:05:19,000
+may be purchased many times.
+
+69
+00:05:19,000 --> 00:05:24,000
+We have hundreds of the same keyboards, or we have hundreds of similar laptops.
+
+70
+00:05:25,000 --> 00:05:30,000
+That's why to implement many to many relationships, one needs a smart table.
+
+71
+00:05:30,000 --> 00:05:37,000
+And in this particular case, we also need to include it in our joint statement to get information that
+
+72
+00:05:37,000 --> 00:05:37,000
+we need.
+
+73
+00:05:38,000 --> 00:05:45,000
+We need to specify conditions that will allow us to map records between different tables, including
+
+74
+00:05:45,000 --> 00:05:46,000
+product table.
+
+75
+00:05:46,000 --> 00:05:50,000
+And when we execute this query, we receive what we expect.
+
+76
+00:05:51,000 --> 00:05:57,000
+In the first task, we are going to use aggregate function to count total number of purchases made by
+
+77
+00:05:57,000 --> 00:06:04,000
+each user after we made select statement to retrieve required information from user and purchase tables.
+
+78
+00:06:04,000 --> 00:06:09,000
+We need to group results by each user in this particular example.
+
+79
+00:06:09,000 --> 00:06:12,000
+I want to group results my last name.
+
+80
+00:06:13,000 --> 00:06:19,000
+You can use analysis if you wish, but probably you already noticed that I use them in all my queries
+
+81
+00:06:19,000 --> 00:06:23,000
+because I used to do them and I find this comfortable.
+
+82
+00:06:24,000 --> 00:06:25,000
+One query is executed.
+
+83
+00:06:26,000 --> 00:06:35,000
+We use user's last name mapped to the total amount of purchases he or she made in our online store in
+
+84
+00:06:35,000 --> 00:06:36,000
+the fifth task.
+
+85
+00:06:36,000 --> 00:06:40,000
+We are going to use the same query as in for stock with small additions.
+
+86
+00:06:40,000 --> 00:06:44,000
+We need to add conditions that will have only records that we need.
+
+87
+00:06:45,000 --> 00:06:47,000
+That's why I have to go by.
+
+88
+00:06:47,000 --> 00:06:53,000
+I write have in close to leaf only users that have more or equal to do purchases.
+
+89
+00:06:54,000 --> 00:06:54,000
+Is it clear?
+
+90
+00:06:55,000 --> 00:06:59,000
+In the six, Starsk, we also use aggregate function.
+
+91
+00:06:59,000 --> 00:07:05,000
+This time we need to find total money amount spent in our online shop by each user.
+
+92
+00:07:06,000 --> 00:07:12,000
+For this, I use some aggregate function to some price of all products that have been purchased by our
+
+93
+00:07:12,000 --> 00:07:13,000
+user.
+
+94
+00:07:14,000 --> 00:07:17,000
+And the same logic we have discussed is applied here.
+
+95
+00:07:18,000 --> 00:07:24,000
+We need to make multiple joints to map all records between each other to extract information we need.
+
+96
+00:07:24,000 --> 00:07:28,000
+In this example, I group result by user last name.
+
+97
+00:07:29,000 --> 00:07:36,000
+Basically, that's all my solution, and that's all homework review, hope that this figure was helpful
+
+98
+00:07:36,000 --> 00:07:41,000
+for you to rack up knowledge nerd in this course and as a reset.
+
+99
+00:07:42,000 --> 00:07:46,000
+Feel free to ask questions in case of any thanks a lot for your attention.
+
+100
+00:07:46,000 --> 00:07:49,000
+Have a great day and see you in the next lesson.
+

51 - ===== SQL Homework Online Shop =====/external-links.txt

@@ -0,0 +1,3 @@
+
+001 Homework-with-links-to-solution
+https://docs.google.com/document/d/10Wz-j_aerkD-Z9A4reYYp9nPS69NF19w71Fq6YU-M50/edit?usp=sharing

52 - JDBC/001 JDBC Overview Establish connection with DB from Java App_en.srt

@@ -0,0 +1,988 @@
+1
+00:00:06,000 --> 00:00:11,000
+Hello, yes, tenants, I'm happy to announce that the day will start super important topic, we are
+
+2
+00:00:11,000 --> 00:00:12,000
+going to learn the ABC.
+
+3
+00:00:13,000 --> 00:00:17,000
+Definitely it will be hard to learn all to this topic and one single lesson.
+
+4
+00:00:17,000 --> 00:00:23,000
+But the day where I learned to learn basic concepts about the ABC understand what it is.
+
+5
+00:00:23,000 --> 00:00:29,000
+And the first practical exercise to establish connection is a database from our Java program.
+
+6
+00:00:30,000 --> 00:00:37,000
+Since this is our first lesson about GBC will start from GBC overview to help you understand what it
+
+7
+00:00:37,000 --> 00:00:38,000
+is and why we need it.
+
+8
+00:00:39,000 --> 00:00:46,000
+After that, we are going to review different GDC driver types to make sure you understand more about
+
+9
+00:00:46,000 --> 00:00:47,000
+database connectivity.
+
+10
+00:00:47,000 --> 00:00:51,000
+I believe it is important to you and learn what Odyssey is.
+
+11
+00:00:52,000 --> 00:00:57,000
+I want to make sure that after this lesson, you understand how the book works.
+
+12
+00:00:57,000 --> 00:01:05,000
+After this piece will jump to practical exercises, we'll learn how to add a driver into the Java app
+
+13
+00:01:06,000 --> 00:01:11,000
+will establish with your connections as a database to make sure that our environment is ready for the
+
+14
+00:01:11,000 --> 00:01:11,000
+next lessons.
+
+15
+00:01:12,000 --> 00:01:14,000
+We have a lot of things to learn today.
+
+16
+00:01:14,000 --> 00:01:15,000
+Let's start.
+
+17
+00:01:16,000 --> 00:01:22,000
+Let's start today from understanding of what you did, this is genuine persistence for Java that the
+
+18
+00:01:22,000 --> 00:01:29,000
+basic connectivity see API implementation used for connecting to a particular type of a database.
+
+19
+00:01:30,000 --> 00:01:36,000
+It is a standard Java API for database and dependent connectivity between the Java programming language
+
+20
+00:01:37,000 --> 00:01:40,000
+and the wide range of databases in similar words.
+
+21
+00:01:41,000 --> 00:01:48,000
+It is a set of glasses and interfaces that allows Java programs to send sequel statements to database.
+
+22
+00:01:48,000 --> 00:01:49,000
+Why is this a standard?
+
+23
+00:01:50,000 --> 00:01:56,000
+Imagine that you have a lot of different Java programs and also you have a lot of different relational
+
+24
+00:01:56,000 --> 00:01:57,000
+database management systems.
+
+25
+00:01:58,000 --> 00:02:04,000
+The question is, should we use unique application programming interface of each relational database
+
+26
+00:02:04,000 --> 00:02:06,000
+management system to perform operations?
+
+27
+00:02:06,000 --> 00:02:13,000
+Was it different protocols and other specifics, for example, unique masses for establishing connection,
+
+28
+00:02:14,000 --> 00:02:20,000
+unique way to execute SQL queries, unique way to read and modify resulting records, and so on.
+
+29
+00:02:20,000 --> 00:02:21,000
+No way.
+
+30
+00:02:22,000 --> 00:02:29,000
+That's why Community Camp was API standard for Java applications to interact with databases, namely
+
+31
+00:02:30,000 --> 00:02:38,000
+set of interfaces, set of masses and once community agreed on the GDC API, each provider of relation
+
+32
+00:02:38,000 --> 00:02:43,000
+that the waste management system provided its own implementation of GDC Driver.
+
+33
+00:02:43,000 --> 00:02:54,000
+So GDC API is just a standard set of API interfaces, and GDC Driver is a concrete implementation is
+
+34
+00:02:54,000 --> 00:03:01,000
+a clear and thus become area of interest of database providers to create implementation of GDC API,
+
+35
+00:03:02,000 --> 00:03:07,000
+because Java getting a lot of popularity and common unique solution was needed.
+
+36
+00:03:07,000 --> 00:03:11,000
+You know that Java could interact with database management system provided.
+
+37
+00:03:12,000 --> 00:03:16,000
+Z, different bus driver types, let's review each of them one by one.
+
+38
+00:03:17,000 --> 00:03:23,000
+The first time that I'd like to describe contains a mapping to another data access API.
+
+39
+00:03:23,000 --> 00:03:25,000
+It is a database driver implementations.
+
+40
+00:03:25,000 --> 00:03:30,000
+It employs the B C driver to connect to the database.
+
+41
+00:03:31,000 --> 00:03:34,000
+The driver converts B C mass it calls into audio.
+
+42
+00:03:34,000 --> 00:03:38,000
+B C function calls logical question from your cycle.
+
+43
+00:03:38,000 --> 00:03:41,000
+B What is or d b c driver?
+
+44
+00:03:42,000 --> 00:03:43,000
+And this is a good question.
+
+45
+00:03:43,000 --> 00:03:46,000
+What do you b c stands for open database connectivity.
+
+46
+00:03:47,000 --> 00:03:52,000
+It is a standard application programming interface for accessing database management systems.
+
+47
+00:03:52,000 --> 00:04:00,000
+The designers of or D B C aims to make it independent of database systems and operating systems, and
+
+48
+00:04:00,000 --> 00:04:07,000
+application written using on the B C can be reported to other platforms both on the client and server
+
+49
+00:04:07,000 --> 00:04:10,000
+side, with few changes to the data access code.
+
+50
+00:04:11,000 --> 00:04:18,000
+What a b c was originally developed by Microsoft and Simba Technologies during the early 1990s.
+
+51
+00:04:19,000 --> 00:04:27,000
+The driver is platform dependent as it makes use of Oadby C, which in turn depends on native libraries
+
+52
+00:04:27,000 --> 00:04:30,000
+of the underlying operating systems the GVM is running.
+
+53
+00:04:30,000 --> 00:04:34,000
+The full advantage of this type of driver is obvious.
+
+54
+00:04:34,000 --> 00:04:42,000
+Almost any database for which the only B C driver is installed can be accessed and data can be retrieved.
+
+55
+00:04:43,000 --> 00:04:48,000
+Regarding the disadvantages of this type of drama, it is worse than the names of fallen ones that ought
+
+56
+00:04:48,000 --> 00:04:49,000
+to be seen.
+
+57
+00:04:49,000 --> 00:04:54,000
+Driver needs to be installed on the client machine performance of her hat sends.
+
+58
+00:04:54,000 --> 00:05:01,000
+The calls have to go so the GBC bridge to the only busy driver centres, a native database connectivity
+
+59
+00:05:01,000 --> 00:05:05,000
+interface thus may be slower than other types of drivers.
+
+60
+00:05:06,000 --> 00:05:10,000
+Specifically, busy drivers are not always available on all platforms.
+
+61
+00:05:11,000 --> 00:05:14,000
+Hence, visibility of this driver is limited.
+
+62
+00:05:15,000 --> 00:05:17,000
+No support from Jarvis and A.
+
+63
+00:05:18,000 --> 00:05:24,000
+The second type of driver is an implementation that uses client side libraries of the target database.
+
+64
+00:05:25,000 --> 00:05:28,000
+It is also called a native API driver.
+
+65
+00:05:28,000 --> 00:05:33,000
+The driver converts semester's calls into native course of the database API.
+
+66
+00:05:34,000 --> 00:05:38,000
+For example, Oracle or assigned driver, is a Typekit driver.
+
+67
+00:05:39,000 --> 00:05:44,000
+We've got an advantage as we can see that performance is better than a type number one driver.
+
+68
+00:05:44,000 --> 00:05:51,000
+That is because there is no implementation of GDP C or D B C reach, but it is also has numerous of
+
+69
+00:05:51,000 --> 00:05:52,000
+disadvantages.
+
+70
+00:05:52,000 --> 00:05:58,000
+Some of them are the vendor client library needs to be installed on the client machine.
+
+71
+00:05:59,000 --> 00:06:06,000
+Not all databases have a client side line, but this driver is a platform dependent type.
+
+72
+00:06:06,000 --> 00:06:12,000
+Number three uses middleware to convert GBC calls into database specific calls.
+
+73
+00:06:12,000 --> 00:06:21,000
+Also known as a network protocol driver is the middle tyre application server converts because directly
+
+74
+00:06:21,000 --> 00:06:24,000
+or indirectly into vendor specific database protocol.
+
+75
+00:06:25,000 --> 00:06:33,000
+This differs from the type for driver in that the protocol conversion logic resides not a decline.
+
+76
+00:06:33,000 --> 00:06:41,000
+Buttons and middle tyre like type for drivers is a type suite driver is written entirely in Java.
+
+77
+00:06:42,000 --> 00:06:48,000
+Advantages of this type of driver are the following ones since the communication between the client
+
+78
+00:06:48,000 --> 00:06:51,000
+and the middle server is database dependent.
+
+79
+00:06:51,000 --> 00:06:58,000
+There is no need for the database when the library on the client is a client needs not to be changed
+
+80
+00:06:58,000 --> 00:06:59,000
+for a new database.
+
+81
+00:07:00,000 --> 00:07:07,000
+Let me go where Sarah can provide typical middleware services like caching of connections, query results,
+
+82
+00:07:08,000 --> 00:07:16,000
+et cetera, load balancing, logging and auditing a single driver can handle any database provided some
+
+83
+00:07:16,000 --> 00:07:17,000
+the middle less courses.
+
+84
+00:07:18,000 --> 00:07:20,000
+I'm on disadvantages of this type of drama.
+
+85
+00:07:20,000 --> 00:07:26,000
+We shouldn't forget about the next ones, requires database specific coding to be done in the middle
+
+86
+00:07:26,000 --> 00:07:26,000
+tyre.
+
+87
+00:07:27,000 --> 00:07:34,000
+Let me know well there and it may result in additional latency, but is typically overcome by using
+
+88
+00:07:34,000 --> 00:07:35,000
+better middleware services.
+
+89
+00:07:36,000 --> 00:07:43,000
+That four connects directly to the database by converting GDP scores into database specific calls,
+
+90
+00:07:44,000 --> 00:07:53,000
+the B c type four driver, also known as a direct database Pure Java driver, is a database driver implementations
+
+91
+00:07:53,000 --> 00:08:00,000
+that converts basic calls directly into vendor specific database protocol written completely in Java
+
+92
+00:08:01,000 --> 00:08:08,000
+that for drivers as thus platform independent, they install inside the Java virtual machine of the
+
+93
+00:08:08,000 --> 00:08:09,000
+client.
+
+94
+00:08:09,000 --> 00:08:16,000
+This provides better performance isn't the type one and type two drivers, as it doesn't have the overhead
+
+95
+00:08:16,000 --> 00:08:21,000
+of conversion, of course, into B C O Database API calls.
+
+96
+00:08:22,000 --> 00:08:26,000
+Unlike the types three drivers, it doesn't need associated software to work.
+
+97
+00:08:27,000 --> 00:08:32,000
+Advantages are completely implemented in Java to achieve platform independence.
+
+98
+00:08:33,000 --> 00:08:41,000
+These drivers don't translate the requests into intermediary format, such as Odyssey Zygmunt application
+
+99
+00:08:41,000 --> 00:08:48,000
+connects directly to the database server, no translation or middleware layers I use, including performance.
+
+100
+00:08:49,000 --> 00:08:54,000
+The man can manage all aspects of the application to database connection.
+
+101
+00:08:54,000 --> 00:09:01,000
+This can facilitate debugging, and regarding these advantages, we must add that drivers database specific
+
+102
+00:09:02,000 --> 00:09:09,000
+has different database vendors to use widely different and usually proprietary network protocols.
+
+103
+00:09:09,000 --> 00:09:13,000
+But I believe this is not a critical disadvantage, considering all advantages.
+
+104
+00:09:14,000 --> 00:09:20,000
+Also, nowadays, all major databases have their own implementation of GitLab, and the only things
+
+105
+00:09:20,000 --> 00:09:26,000
+that you need to do is to add the basic driver into the class of your Java app.
+
+106
+00:09:27,000 --> 00:09:30,000
+So now, you know, different types of GBC driver.
+
+107
+00:09:31,000 --> 00:09:36,000
+Probably you already understood that we are going to learn how to work was GBC type four?
+
+108
+00:09:36,000 --> 00:09:39,000
+Let's recap one more time how it works.
+
+109
+00:09:39,000 --> 00:09:41,000
+We are going to have program code.
+
+110
+00:09:42,000 --> 00:09:44,000
+This can be any problem codes.
+
+111
+00:09:44,000 --> 00:09:52,000
+It performs operations with persistent storage in my course, Java from zero to the first job we create
+
+112
+00:09:52,000 --> 00:09:54,000
+online shop and the margins.
+
+113
+00:09:54,000 --> 00:10:01,000
+And during the user registration, we ran some codes that should store user before learning databases,
+
+114
+00:10:01,000 --> 00:10:03,000
+we store its users and file.
+
+115
+00:10:03,000 --> 00:10:10,000
+Now that code will interact with GDC API using standard interfaces.
+
+116
+00:10:10,000 --> 00:10:18,000
+GBC API will use implementation of the API, namely GBC driver for specific database management system
+
+117
+00:10:19,000 --> 00:10:24,000
+and Z Driver will set com Monsters database management system to execute sequel queries.
+
+118
+00:10:25,000 --> 00:10:28,000
+Here in the slides, you can see how it works.
+
+119
+00:10:29,000 --> 00:10:36,000
+Let's now have a lot of them, and I will show you how to add the busy driver to your app and establish
+
+120
+00:10:36,000 --> 00:10:37,000
+connection with the database.
+
+121
+00:10:38,000 --> 00:10:44,000
+In this lesson, we are going to do everything from configuration side to be sure that our development
+
+122
+00:10:44,000 --> 00:10:47,000
+environment is all set for the following lessons.
+
+123
+00:10:47,000 --> 00:10:54,000
+The first thing that we have to do is to get busy drivers that we need help to understand what driver
+
+124
+00:10:54,000 --> 00:10:57,000
+we need and where to download it very easily.
+
+125
+00:10:58,000 --> 00:11:01,000
+Just open your browser and make a Google search.
+
+126
+00:11:01,000 --> 00:11:04,000
+You have to type Mavin the wrapper for us.
+
+127
+00:11:04,000 --> 00:11:06,000
+This is a repository is a source.
+
+128
+00:11:06,000 --> 00:11:10,000
+A lot of artifacts libraries for Java development.
+
+129
+00:11:10,000 --> 00:11:15,000
+After that puts the name of your database management system and writes GBC.
+
+130
+00:11:16,000 --> 00:11:21,000
+Google search will show you page that should leave you to name a repository.
+
+131
+00:11:21,000 --> 00:11:24,000
+In our case, we have my school installed.
+
+132
+00:11:24,000 --> 00:11:27,000
+That's why I select my school connector.
+
+133
+00:11:28,000 --> 00:11:34,000
+Depending on the version of database management systems that you installed on your computer, you have
+
+134
+00:11:34,000 --> 00:11:36,000
+to select driver of the same version.
+
+135
+00:11:36,000 --> 00:11:40,000
+It will be enough to know at least major version now.
+
+136
+00:11:40,000 --> 00:11:43,000
+Case you installed my sequel of version eight.
+
+137
+00:11:44,000 --> 00:11:51,000
+That's why I select Here's the latest version available, and here we can download Java, then load
+
+138
+00:11:51,000 --> 00:11:52,000
+it on your PC.
+
+139
+00:11:53,000 --> 00:12:01,000
+Once, to the knowledge, we have to add that into the ClassPass of your project in I.D. In our case,
+
+140
+00:12:01,000 --> 00:12:02,000
+we are going to use Eclipse.
+
+141
+00:12:03,000 --> 00:12:09,000
+Let me quickly show you how to that external John to ClassPass in Eclipse Mouse.
+
+142
+00:12:09,000 --> 00:12:16,000
+Click on your project after that select Built Boss and after that, click on Configure Builds Pass Select
+
+143
+00:12:16,000 --> 00:12:17,000
+Libraries tab.
+
+144
+00:12:18,000 --> 00:12:20,000
+Click on ClassPass Boss.
+
+145
+00:12:20,000 --> 00:12:23,000
+And after that, click on Add External Jar.
+
+146
+00:12:23,000 --> 00:12:26,000
+After we can click Apply Close.
+
+147
+00:12:27,000 --> 00:12:27,000
+Great.
+
+148
+00:12:28,000 --> 00:12:35,000
+Now we have my sequel GBC Driver in our class boss, and we are ready to proceed with writing the code
+
+149
+00:12:35,000 --> 00:12:37,000
+to establish connection with our database.
+
+150
+00:12:38,000 --> 00:12:44,000
+All examples related to GDC will be stored in the separate package that is called GDC.
+
+151
+00:12:45,000 --> 00:12:51,000
+You can find the reference to the court examples that I'm going to show you in this lesson in attachments
+
+152
+00:12:51,000 --> 00:12:52,000
+to the lesson.
+
+153
+00:12:53,000 --> 00:12:55,000
+And now we are going through U.
+
+154
+00:12:55,000 --> 00:12:59,000
+S. Connection example file in this file, we have made massive.
+
+155
+00:13:00,000 --> 00:13:01,000
+And we can run it.
+
+156
+00:13:01,000 --> 00:13:05,000
+Let me go line by line to explain what we have here.
+
+157
+00:13:06,000 --> 00:13:13,000
+If you try to find tutorial in the internet about establishing connection with the database, most likely
+
+158
+00:13:13,000 --> 00:13:20,000
+you will find a lot of tutorials, whereas the first step is uploading driver loss into class boss in
+
+159
+00:13:20,000 --> 00:13:23,000
+a modern environment and in our environments setup.
+
+160
+00:13:24,000 --> 00:13:31,000
+This is not needed since all UBC drivers at the fountains across ClassPass automatically loaded, but
+
+161
+00:13:31,000 --> 00:13:38,000
+just in case I leave comments lines of code that demonstrates how to upload a class into a G.M..
+
+162
+00:13:39,000 --> 00:13:40,000
+Why is this is needed?
+
+163
+00:13:40,000 --> 00:13:49,000
+I mean, the lower driver class when you load driver class like this, or it is loaded into G.M. automatically,
+
+164
+00:13:49,000 --> 00:13:53,000
+according to general rules, static initialization is executed.
+
+165
+00:13:54,000 --> 00:14:00,000
+So let's open driver clusters code and investigate what is in the aesthetic consideration.
+
+166
+00:14:00,000 --> 00:14:05,000
+Love my school connector has open source code available on the top.
+
+167
+00:14:06,000 --> 00:14:11,000
+And here's how a driver class looks like you can find steady consolidation.
+
+168
+00:14:11,000 --> 00:14:17,000
+Look here where driver manager is used to register instance of the current driver.
+
+169
+00:14:18,000 --> 00:14:20,000
+That's why it is enough.
+
+170
+00:14:20,000 --> 00:14:26,000
+This class just to be loaded into the gym to perform all necessary configurations.
+
+171
+00:14:27,000 --> 00:14:34,000
+But as I said in our case, Joe will identify a driver in the class bus automatically and will load
+
+172
+00:14:34,000 --> 00:14:42,000
+driver class driver manager is one out of many classes from Java School Package that will use basically
+
+173
+00:14:42,000 --> 00:14:45,000
+Angeliki all classes related to school.
+
+174
+00:14:45,000 --> 00:14:52,000
+A group into Java School Package Driver Manager is a clause that is responsible for managing GBC.
+
+175
+00:14:52,000 --> 00:14:57,000
+Drivers also will use this class to create objects of connection type.
+
+176
+00:14:57,000 --> 00:15:00,000
+This will be used to execute SQL statements.
+
+177
+00:15:00,000 --> 00:15:06,000
+Once we are sure that driver is uploaded into the JVM, we need to establish connection.
+
+178
+00:15:07,000 --> 00:15:14,000
+Similar to other resources, we need to make sure that all resources are properly closed after they
+
+179
+00:15:14,000 --> 00:15:15,000
+were used.
+
+180
+00:15:16,000 --> 00:15:19,000
+That's why we use drivers resources below.
+
+181
+00:15:19,000 --> 00:15:25,000
+If you're not familiar with this blog, review the details in my complete Java course.
+
+182
+00:15:25,000 --> 00:15:33,000
+In the input output stream, top insured resources declared in Trailers Resources blog will be automatically
+
+183
+00:15:33,000 --> 00:15:36,000
+closed after the blog will be completely executed.
+
+184
+00:15:37,000 --> 00:15:42,000
+Java guarantees this and responsible for proper closure of their sources.
+
+185
+00:15:43,000 --> 00:15:49,000
+You can put on this blog only Typekit that implements articles about interface.
+
+186
+00:15:50,000 --> 00:15:56,000
+We use drama manager to get connection object, get connection mass, it is overloaded and we can use
+
+187
+00:15:56,000 --> 00:15:58,000
+different versions of it.
+
+188
+00:15:59,000 --> 00:16:00,000
+But there is the same.
+
+189
+00:16:01,000 --> 00:16:06,000
+You have to pass host of your SQL server where that the base is located and credentials.
+
+190
+00:16:07,000 --> 00:16:13,000
+You can see that overloaded masses might take is a string, and properties and brokerages says this
+
+191
+00:16:13,000 --> 00:16:16,000
+case will contain information about user and passwords.
+
+192
+00:16:17,000 --> 00:16:18,000
+Or you can pass one concatenate.
+
+193
+00:16:18,000 --> 00:16:23,000
+A string was all acquired information on three separate suites.
+
+194
+00:16:23,000 --> 00:16:25,000
+In our case, we pass three strings.
+
+195
+00:16:26,000 --> 00:16:28,000
+Let's look at what actually would pass here.
+
+196
+00:16:29,000 --> 00:16:33,000
+We concatenate hostname and database name as a first message argument.
+
+197
+00:16:34,000 --> 00:16:36,000
+After that, we pass user and password.
+
+198
+00:16:37,000 --> 00:16:43,000
+Definitely storing database credentials in the source code file is not the best practice, but for demo
+
+199
+00:16:43,000 --> 00:16:46,000
+purposes and for first, the basic program.
+
+200
+00:16:46,000 --> 00:16:48,000
+I believe for this, OK?
+
+201
+00:16:48,000 --> 00:16:54,000
+Later, when we will keep implementing our online store, I will show you where to put credentials.
+
+202
+00:16:55,000 --> 00:17:01,000
+Database name is the one that we created together in the last database.
+
+203
+00:17:01,000 --> 00:17:08,000
+If you remember, we created a database for our online store project here just to use its name.
+
+204
+00:17:09,000 --> 00:17:14,000
+Name of the schema, user and passwords is pretty clear and simple.
+
+205
+00:17:14,000 --> 00:17:22,000
+But let's look at the host name and understand how it looks like it contains that prefix and actually
+
+206
+00:17:22,000 --> 00:17:23,000
+is a euro.
+
+207
+00:17:23,000 --> 00:17:26,000
+This a host where our SQL server is running.
+
+208
+00:17:27,000 --> 00:17:31,000
+In our case, this is localhost and default port.
+
+209
+00:17:32,000 --> 00:17:35,000
+But how did they define which graphics to use?
+
+210
+00:17:35,000 --> 00:17:39,000
+Because it's a little bit different for connection with different database management systems.
+
+211
+00:17:39,000 --> 00:17:44,000
+This year, around establishes a database connection was a Java embedded driver.
+
+212
+00:17:45,000 --> 00:17:53,000
+The Java DB also includes and that's where Client Driver, which uses a different URL typically in the
+
+213
+00:17:53,000 --> 00:17:53,000
+database you.
+
+214
+00:17:54,000 --> 00:18:02,000
+You use the B c word column and database management system name, for example, to create the URL to
+
+215
+00:18:02,000 --> 00:18:04,000
+establish connection with their database.
+
+216
+00:18:05,000 --> 00:18:08,000
+You would write GBC Derbyshire for possibly a.
+
+217
+00:18:09,000 --> 00:18:15,000
+You will use PostgreSQL words here, and we establish in connection to my SQL that the best measurement
+
+218
+00:18:15,000 --> 00:18:16,000
+system.
+
+219
+00:18:16,000 --> 00:18:18,000
+That's why I have my sequel here.
+
+220
+00:18:19,000 --> 00:18:19,000
+Do you understand?
+
+221
+00:18:20,000 --> 00:18:26,000
+Anyway, you can always check this kind of detail in the documentation or by simply searching the internet.
+
+222
+00:18:27,000 --> 00:18:29,000
+The main part and that should be followed here.
+
+223
+00:18:29,000 --> 00:18:33,000
+I describe after we called get a connection method.
+
+224
+00:18:34,000 --> 00:18:36,000
+The connection variable should be initialized.
+
+225
+00:18:37,000 --> 00:18:41,000
+If for some reason it is now, that means connection wasn't that thing.
+
+226
+00:18:42,000 --> 00:18:48,000
+If it is not now, then let's congratulate ourselves with successfully established connection.
+
+227
+00:18:49,000 --> 00:18:55,000
+Let's run our application and we can see that connection established successfully.
+
+228
+00:18:56,000 --> 00:18:59,000
+Your connection may throw a sequel exception.
+
+229
+00:18:59,000 --> 00:19:04,000
+It may be thrown if a database access error occurs was a URL.
+
+230
+00:19:04,000 --> 00:19:10,000
+Is now also a child exception, maybe strong that is sequel to Mount Exception.
+
+231
+00:19:11,000 --> 00:19:17,000
+It may be thrown when the driver has determined that the timeout specified by the set logging timeout
+
+232
+00:19:17,000 --> 00:19:24,000
+method has been ICSI and has at least tried to cancel the current database connection at them.
+
+233
+00:19:25,000 --> 00:19:28,000
+That's why I handle potential SQL exception here.
+
+234
+00:19:29,000 --> 00:19:33,000
+That's it, and you can see that connection is successfully established.
+
+235
+00:19:33,000 --> 00:19:34,000
+Congrats.
+
+236
+00:19:35,000 --> 00:19:38,000
+That's all what I plans to cover in this lesson.
+
+237
+00:19:38,000 --> 00:19:40,000
+Let's recap what we have learned today.
+
+238
+00:19:41,000 --> 00:19:49,000
+In this lesson, we hold GDC overview and learn what is the B C s Valorant different GBC driver types?
+
+239
+00:19:50,000 --> 00:19:51,000
+I explained you.
+
+240
+00:19:51,000 --> 00:19:55,000
+What are the B c es after this lesson?
+
+241
+00:19:55,000 --> 00:19:57,000
+I believe you have understanding how do the do works?
+
+242
+00:19:58,000 --> 00:20:06,000
+And in real life example, I showed you how to add GBC driver into a Java project and establish connection
+
+243
+00:20:06,000 --> 00:20:08,000
+from your Java program with a database.
+
+244
+00:20:08,000 --> 00:20:11,000
+Now we are ready for the next lesson.
+
+245
+00:20:12,000 --> 00:20:13,000
+That's it for this lesson.
+
+246
+00:20:14,000 --> 00:20:15,000
+Thanks a lot for your attention.
+
+247
+00:20:15,000 --> 00:20:18,000
+Have a great day and see you in the next lesson.
+

52 - JDBC/001 Source-code-example-from-the-lesson.url

@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://github.com/AndriiPiatakha/learnit_java_core/tree/master/src/com/itbulls/learnit/javacore/jdbc