pre-view/CS50-raw · Datasets at Hugging Face

text stringlengths 1 81	start float64 0 10.1k	duration float64 0 24.9
this value for me.	692.18	1.44
Let me try leaving off "id" in this case.	693.62	2.82
I'll omit the "id" altogether, which seems	696.44	2.91
at first like a bit of a bad thought, like shouldn't every row	699.35	2.82
have its own id?	702.17	1.11
Well, let's just try and figure out what happened.	703.28	2.55
I'll hit Enter here.	705.83	1.23
And now I'll say, let me give the VALUES.	707.06	2.5
Well, now the first column is the title column.	709.56	3.21
So I'll go ahead and say that this one will be called "Spring outing."	712.77	3.2
We're going to add this one to our collection here.	715.97	2.55
The accession number, in this case, is 14.76.	718.52	3.09
And we acquired this one all the way back in 1914-01-08 [? semicolon. ?]	721.61	6.93
So I'll hit Enter here.	728.54	1.63
And notice how there's no [? id ?] that I have specified.	730.17	3.17
But now if I hit Enter, seems to work.	733.34	3.51
I'll type SELECT [? star ?] [? FROM ?] "collections,"	736.85	3.27
and what do I see but the new primary key of 3.	740.12	4.59
So it seems like SQLite actually increments the primary key for me.	744.71	5.58
If I add some new row, it looks, what is the current highest primary key	750.29	4.89
and adds 1 to that automatically for me.	755.18	2.94
And I've gotten that by specifying in my schema	758.12	3.27
this primary key constraint down on line 6.	761.39	3.66
So pretty handy for me here.	765.05	2.79
I see a few other questions too.	767.84	2.19
So let's take those before we move on as well.	770.03	4.54
Let's go to [? Andre. ?]	774.57	1.19
SPEAKER 3: I just want to ask if I delete the, let's say,	775.76	3.27
the [? first ?] record and type again, will it number it [? on ?] the fourth	779.03	7.38
number or the first one.	786.41	1.093
SPEAKER 1: A great question.	787.503	1.167
We'll see this a little bit later on too.	788.67	1.708
But if I delete some row, let's say, I deleted the row with primary key of 1,	790.378	4.612
well, what SQLite will do, at least by default,	794.99	3
is actually take the highest value.	797.99	2.07
Let's say the highest value is still three in my database.	800.06	3.28
It will add 1 to that, and I want to insert that new row it'll	803.34	3.17
have the [? id ?] of 4 in this case.	806.51	3.163
OK, so let's explore a bit more some of these constraints on tables.	809.673	4.757
Here, we're talking about the primary key constraint, but we also have,	814.43	3.42
as we saw before, the [? NOT ?] [? NULL ?] constraint	817.85	2.46
and the [? UNIQUE ?] constraint.	820.31	1.69
So let's try inserting given those constraints here.	822	3.23
[? I'll go ?] back to my computer.	825.23	2.05
And again, notice in my schema, I specified that this "title"	827.28	5.06
column should always be NOT NULL.	832.34	3.172
It should never have a [? null ?] value inside of it.	835.512	2.208
And similarly, "accession_number" should also be NOT NULL.	837.72	3.56
It should also be [? unique. ?] I should have no two rows	841.28	3.99
that have the same accession number.	845.27	2.28
And maybe kind of a playfully, subversively here,	847.55	3.75
let's try to run against this constraint.	851.3	2.158
Let's actually try to add the same accession number and see what happens.	853.458	3.042
So I'll come back to my [? TERMINAL. ?] Let me just reinsert,	856.5	4.4
let's say "Spring outing."	860.9	1.59
Notice how if I SELECT [? star ?] FROM "collections," it's already in here.	862.49	4.81
But I'll try to add it yet again with the same [? accession ?] [? number. ?]	867.3	3.45
So I'll say INSERT INTO "collections."	870.75	1.658
And by now this is [? hopefully ?] [? becoming ?] a little more familiar.	872.408	3.042
I now want to say the columns I want to add data to.	875.45	3.42
So I'll say the "title" column, the "accession_number" column,	878.87	7.65
and also the "acquired" date I'll hit Enter.	886.52	3.03
And now I'll say the VALUES again.	889.55	2.07
Let's reinsert [? "Spring ?] [? outing." ?] I'll say "Spring outing"	891.62	3.03
as a title, the accession number is 14.76,	894.65	3.99
and the date it was acquired was again 1914-01-08 semicolon.	898.64	6.03
Now if I hit Enter, what do we see?	904.67	4.43
Runtime error-- UNIQUE constraint failed.	909.1	3.39
So it seems we ran against this constraint	912.49	2.4
here that we specified on line 4 here.	914.89	3.57
[? "Accession number" ?] should always be unique.	918.46	2.37
But by trying to add a new row that had that same accession number,	920.83	3.99
we ran into this runtime error and our operation was not completed.	924.82	4.96
If I say in this case, SELECT [? star ?] FROM "collections,"	929.78	3.41
notice how I guarded myself from adding Spring outing more than once	933.19	4.86
with the same accession number.	938.05	2.02
So some usefulness here to these kinds of constraints.	940.07	3.56
Let's try violating NOT NULL too.	943.63	2.55
I'll try adding a title that is actually [? null, ?] non-existent.	946.18	3.072
It's trying to add a painting without a title itself.	949.252	2.208
Let's try this.	951.46	0.96
I might try INSERT INTO the "collections" table,	952.42	3.6
and I'll add to the "title" columns, the "accession_number," and also	956.02	5.64
the "acquired" column.	961.66	2.28
Now, I'll say the VALUES here.	963.94	2.08
But remember, this [? null ?] value.	966.02	1.85
Null meaning nothing.	967.87	1.41
This value doesn't exist.	969.28	1.35
I could insert that into my table, or at least try to.	970.63	3.63
I'll say NULL is a title.	974.26	2.43
And similarly, NULL is the accession number.	976.69	2.92
Now let's say, just playfully, we got this painting back in 1900-01-10	979.61	5.84
like this.	985.45	1.32
OK now, semicolon.	986.77	2.19
I'll hit Enter, and we see the same runtime error-- constraint failed,	988.96	5.01
in this case, the NOT NULL constraint.	993.97	2.23
So notice again how in my schema, I specified "title" should be NOT NULL.	996.2	5.75
But here when I try to insert a [? null ?] [? value, ?] I run into that	1,001.95	4.14
constraint and I can't insert that value.	1,006.09	2.58
If I try to SELECT [? star ?] FROM "collections,"	1,008.67	2.73

this value for me.

692.18

1.44

Let me try leaving off "id" in this case.

693.62

2.82

I'll omit the "id" altogether, which seems

696.44

2.91

at first like a bit of a bad thought, like shouldn't every row

699.35

2.82

have its own id?

702.17

1.11

Well, let's just try and figure out what happened.

703.28

2.55

I'll hit Enter here.

705.83

1.23

And now I'll say, let me give the VALUES.

707.06

2.5

Well, now the first column is the title column.

709.56

3.21

So I'll go ahead and say that this one will be called "Spring outing."

712.77

3.2

We're going to add this one to our collection here.

715.97

2.55

The accession number, in this case, is 14.76.

718.52

3.09

And we acquired this one all the way back in 1914-01-08 [? semicolon. ?]

721.61

6.93

So I'll hit Enter here.

728.54

1.63

And notice how there's no [? id ?] that I have specified.

730.17

3.17

But now if I hit Enter, seems to work.

733.34

3.51

I'll type SELECT [? star ?] [? FROM ?] "collections,"

736.85

3.27

and what do I see but the new primary key of 3.

740.12

4.59

So it seems like SQLite actually increments the primary key for me.

744.71

5.58

If I add some new row, it looks, what is the current highest primary key

750.29

4.89

and adds 1 to that automatically for me.

755.18

2.94

And I've gotten that by specifying in my schema

758.12

3.27

this primary key constraint down on line 6.

761.39

3.66

So pretty handy for me here.

765.05

2.79

I see a few other questions too.

767.84

2.19

So let's take those before we move on as well.

770.03

4.54

Let's go to [? Andre. ?]

774.57

1.19

SPEAKER 3: I just want to ask if I delete the, let's say,

775.76

3.27

the [? first ?] record and type again, will it number it [? on ?] the fourth

779.03

7.38

number or the first one.

786.41

1.093

SPEAKER 1: A great question.

787.503

1.167

We'll see this a little bit later on too.

788.67

1.708

But if I delete some row, let's say, I deleted the row with primary key of 1,

790.378

4.612

well, what SQLite will do, at least by default,

794.99

3

is actually take the highest value.

797.99

2.07

Let's say the highest value is still three in my database.

800.06

3.28

It will add 1 to that, and I want to insert that new row it'll

803.34

3.17

have the [? id ?] of 4 in this case.

806.51

3.163

OK, so let's explore a bit more some of these constraints on tables.

809.673

4.757

Here, we're talking about the primary key constraint, but we also have,

814.43

3.42

as we saw before, the [? NOT ?] [? NULL ?] constraint

817.85

2.46

and the [? UNIQUE ?] constraint.

820.31

1.69

So let's try inserting given those constraints here.

822

3.23

[? I'll go ?] back to my computer.

825.23

2.05

And again, notice in my schema, I specified that this "title"

827.28

5.06

column should always be NOT NULL.

832.34

3.172

It should never have a [? null ?] value inside of it.

835.512

2.208

And similarly, "accession_number" should also be NOT NULL.

837.72

3.56

It should also be [? unique. ?] I should have no two rows

841.28

3.99

that have the same accession number.

845.27

2.28

And maybe kind of a playfully, subversively here,

847.55

3.75

let's try to run against this constraint.

851.3

2.158

Let's actually try to add the same accession number and see what happens.

853.458

3.042

So I'll come back to my [? TERMINAL. ?] Let me just reinsert,

856.5

4.4

let's say "Spring outing."

860.9

1.59

Notice how if I SELECT [? star ?] FROM "collections," it's already in here.

862.49

4.81

But I'll try to add it yet again with the same [? accession ?] [? number. ?]

867.3

3.45

So I'll say INSERT INTO "collections."

870.75

1.658

And by now this is [? hopefully ?] [? becoming ?] a little more familiar.

872.408

3.042

I now want to say the columns I want to add data to.

875.45

3.42

So I'll say the "title" column, the "accession_number" column,

878.87

7.65

and also the "acquired" date I'll hit Enter.

886.52

3.03

And now I'll say the VALUES again.

889.55

2.07

Let's reinsert [? "Spring ?] [? outing." ?] I'll say "Spring outing"

891.62

3.03

as a title, the accession number is 14.76,

894.65

3.99

and the date it was acquired was again 1914-01-08 semicolon.

898.64

6.03

Now if I hit Enter, what do we see?

904.67

4.43

Runtime error-- UNIQUE constraint failed.

909.1

3.39

So it seems we ran against this constraint

912.49

2.4

here that we specified on line 4 here.

914.89

3.57

[? "Accession number" ?] should always be unique.

918.46

2.37

But by trying to add a new row that had that same accession number,

920.83

3.99

we ran into this runtime error and our operation was not completed.

924.82

4.96

If I say in this case, SELECT [? star ?] FROM "collections,"

929.78

3.41

notice how I guarded myself from adding Spring outing more than once

933.19

4.86

with the same accession number.

938.05

2.02

So some usefulness here to these kinds of constraints.

940.07

3.56

Let's try violating NOT NULL too.

943.63

2.55

I'll try adding a title that is actually [? null, ?] non-existent.

946.18

3.072

It's trying to add a painting without a title itself.

949.252

2.208

Let's try this.

951.46

0.96

I might try INSERT INTO the "collections" table,

952.42

3.6

and I'll add to the "title" columns, the "accession_number," and also

956.02

5.64

the "acquired" column.

961.66

2.28

Now, I'll say the VALUES here.

963.94

2.08

But remember, this [? null ?] value.

966.02

1.85

Null meaning nothing.

967.87

1.41

This value doesn't exist.

969.28

1.35

I could insert that into my table, or at least try to.

970.63

3.63

I'll say NULL is a title.

974.26

2.43

And similarly, NULL is the accession number.

976.69

2.92

Now let's say, just playfully, we got this painting back in 1900-01-10

979.61

5.84

like this.

985.45

1.32

OK now, semicolon.

986.77

2.19

I'll hit Enter, and we see the same runtime error-- constraint failed,

988.96

5.01

in this case, the NOT NULL constraint.

993.97

2.23

So notice again how in my schema, I specified "title" should be NOT NULL.

996.2

5.75

But here when I try to insert a [? null ?] [? value, ?] I run into that

1,001.95

4.14

constraint and I can't insert that value.

1,006.09

2.58

If I try to SELECT [? star ?] FROM "collections,"

1,008.67

2.73