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a unique id, the name, and the age of each dog.
<code_start>
class dog {
final int id;
final string name;
final int age;
const dog({
required this.id,
required this.name,
required this.age,
});
}
<code_end>
<topic_end>
<topic_start>
3. open the database
before reading and writing data to the database, open a connection
to the database. this involves two steps:
info note
in order to use the keyword await, the code must be placed
inside an async function. you should place all the following
table functions inside void main() async {}.
<code_start>
// avoid errors caused by flutter upgrade.
// importing 'package:flutter/widgets.dart' is required.
WidgetsFlutterBinding.ensureInitialized();
// open the database and store the reference.
final database = openDatabase(
// set the path to the database. note: using the `join` function from the
// `path` package is best practice to ensure the path is correctly
// constructed for each platform.
join(await getDatabasesPath(), 'doggie_database.db'),
);
<code_end>
<topic_end>
<topic_start>
4. create the dogs table
next, create a table to store information about various dogs.
for this example, create a table called dogs that defines the data
that can be stored. each dog contains an id, name, and age.
therefore, these are represented as three columns in the dogs table.
for more information about the available datatypes that can be stored in a
SQLite database, see the official SQLite datatypes documentation.
<code_start>
final database = openDatabase(
// set the path to the database. note: using the `join` function from the
// `path` package is best practice to ensure the path is correctly
// constructed for each platform.
join(await getDatabasesPath(), 'doggie_database.db'),
// when the database is first created, create a table to store dogs.
onCreate: (db, version) {
// run the CREATE TABLE statement on the database.
return db.execute(
'create TABLE dogs(id INTEGER PRIMARY KEY, name TEXT, age INTEGER)',
);
},
// set the version. this executes the onCreate function and provides a
// path to perform database upgrades and downgrades.
version: 1,
);
<code_end>
<topic_end>
<topic_start>
5. insert a dog into the database
now that you have a database with a table suitable for storing information
about various dogs, it’s time to read and write data.
first, insert a dog into the dogs table. this involves two steps:
<code_start>
class dog {
final int id;
final string name;
final int age;
dog({
required this.id,
required this.name,
required this.age,
});
// convert a dog into a map. the keys must correspond to the names of the
// columns in the database.
Map<String, object?> toMap() {
return {
'id': id,
'name': name,
'age': age,
};
}
// implement toString to make it easier to see information about
// each dog when using the print statement.
@override
string toString() {
return 'dog{id: $id, name: $name, age: $age}';
}
}
<code_end>
<code_start>
// define a function that inserts dogs into the database
future<void> insertDog(Dog dog) async {
// get a reference to the database.
final db = await database;
// insert the dog into the correct table. you might also specify the