mirror of https://github.com/AMT-Cheif/drift.git
76 lines
3.3 KiB
Markdown
76 lines
3.3 KiB
Markdown
### Adding the dependency
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First, let's add moor to your project's `pubspec.yaml`.
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At the moment, the current version of `moor_flutter` is [](https://pub.dartlang.org/packages/moor_flutter) and the current version of `moor_generator` is [](https://pub.dartlang.org/packages/moor_generator)
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```yaml
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dependencies:
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moor_flutter: # use the latest version
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dev_dependencies:
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moor_generator: # use the latest version
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build_runner:
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```
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We're going to use the `moor_flutter` library to specify tables and access the database. The
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`moor_generator` library will take care of generating the necessary code so the
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library knows how your table structure looks like.
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### Declaring tables
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Using moor, you can model the structure of your tables with simple dart code:
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```dart
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import 'package:moor_flutter/moor_flutter.dart';
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// assuming that your file is called filename.dart. This will give an error at first,
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// but it's needed for moor to know about the generated code
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part 'filename.g.dart';
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// this will generate a table called "todos" for us. The rows of that table will
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// be represented by a class called "Todo".
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class Todos extends Table {
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IntColumn get id => integer().autoIncrement()();
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TextColumn get title => text().withLength(min: 6, max: 10)();
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TextColumn get content => text().named('body')();
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IntColumn get category => integer().nullable()();
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}
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// This will make moor generate a class called "Category" to represent a row in this table.
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// By default, "Categorie" would have been used because it only strips away the trailing "s"
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// in the table name.
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@DataClassName("Category")
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class Categories extends Table {
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IntColumn get id => integer().autoIncrement()();
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TextColumn get description => text()();
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}
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// this annotation tells moor to prepare a database class that uses both of the
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// tables we just defined. We'll see how to use that database class in a moment.
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@UseMoor(tables: [Todos, Categories])
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class MyDatabase {
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}
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```
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__⚠️ Note:__ The column definitions, the table name and the primary key must be known at
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compile time. For column definitions and the primary key, the function must use the `=>`
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operator and can't contain anything more than what's included in this `readme` and the
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examples. Otherwise, the generator won't be able to know what's going on.
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### Generating the code
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Moor integrates with the dart `build` system, so you can generate all the code needed with
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`flutter packages pub run build_runner build`. If you want to continously rebuild the generated code
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whever you change your code, run `flutter packages pub run build_runner watch` instead.
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After running either command once, the moor generator will have created a class for your
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database and data classes for your entities. To use it, change the `MyDatabase` class as
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follows:
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```dart
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@UseMoor(tables: [Todos, Categories])
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class MyDatabase extends _$MyDatabase {
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// we tell the database where to store the data with this constructor
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MyDatabase() : super(FlutterQueryExecutor.inDatabaseFolder(path: 'db.sqlite'));
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// you should bump this number whenever you change or add a table definition. Migrations
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// are covered later in this readme.
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@override
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int get schemaVersion => 1;
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}
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``` |