moor_flutter 1.3.0
moor_flutter: ^1.3.0 copied to clipboard
Flutter implementation of moor, a safe and reactive persistence library for Dart applications
Moor #
Moor is an easy to use, reactive persistence library for Flutter apps. Define your database tables in pure Dart and enjoy a fluent query API, auto-updating streams and more!
Getting started #
For a more detailed guide on using moor, check out the documentation.
Adding the dependency #
First, add moor to your project's pubspec.yaml
.
dependencies:
moor_flutter: # use the latest version
dev_dependencies:
moor_generator: # use the latest versions
build_runner:
Declaring tables #
You can use the DSL included with this library to specify your libraries with simple dart code:
import 'package:moor_flutter/moor_flutter.dart';
// assuming that your file is called filename.dart. This will give an error at first,
// but it's needed for moor to know about the generated code
part 'filename.g.dart';
// this will generate a table called "todos" for us. The rows of that table will
// be represented by a class called "Todo".
class Todos extends Table {
IntColumn get id => integer().autoIncrement()();
TextColumn get title => text().withLength(min: 6, max: 10)();
TextColumn get content => text().named('body')();
IntColumn get category => integer().nullable()();
}
// This will make moor generate a class called "Category" to represent a row in this table.
// By default, "Categorie" would have been used because it only strips away the trailing "s"
// in the table name.
@DataClassName("Category")
class Categories extends Table {
IntColumn get id => integer().autoIncrement()();
TextColumn get description => text()();
}
// this annotation tells moor to prepare a database class that uses both of the
// tables we just defined. We'll see how to use that database class in a moment.
@UseMoor(tables: [Todos, Categories])
class MyDatabase {
}
⚠️ Note: The column definitions, the table name and the primary key must be known at
compile time. For column definitions and the primary key, the function must use the =>
operator and can't contain anything more than what's included in this readme
and the
examples. Otherwise, the generator won't be able to know what's going on.
Generating the code #
Moor integrates with the dart build
system, so you can generate all the code needed with
flutter packages pub run build_runner build
. If you want to continuously rebuild the generated code
whenever you change your code, run flutter packages pub run build_runner watch
instead.
After running either command once, the moor generator will have created a class for your
database and data classes for your entities. To use it, change the MyDatabase
class as
follows:
@UseMoor(tables: [Todos, Categories])
class MyDatabase extends _$MyDatabase {
// we tell the database where to store the data with this constructor
MyDatabase() : super(FlutterQueryExecutor.inDatabaseFolder(path: 'db.sqlite'));
// you should bump this number whenever you change or add a table definition. Migrations
// are covered later in this readme.
@override
int get schemaVersion => 1;
}
You can ignore the schemaVersion
at the moment, the important part is that you can
now run your queries with fluent Dart code:
Writing queries #
// inside the database class:
// loads all todo entries
Future<List<Todo>> get allTodoEntries => select(todos).get();
// watches all todo entries in a given category. The stream will automatically
// emit new items whenever the underlying data changes.
Stream<List<TodoEntry>> watchEntriesInCategory(Category c) {
return (select(todos)..where((t) => t.category.equals(c.id))).watch();
}
}