drift 2.20.3 drift: ^2.20.3 copied to clipboard
Drift is a reactive library to store relational data in Dart and Flutter applications.
// For more information on using drift, please see https://drift.simonbinder.eu/docs/getting-started/
// A full cross-platform example is available here: https://github.com/simolus3/drift/tree/develop/examples/app
import 'package:drift/drift.dart';
import 'package:drift/native.dart';
part 'main.g.dart';
@DataClassName('TodoCategory')
class TodoCategories extends Table {
IntColumn get id => integer().autoIncrement()();
TextColumn get name => text()();
}
@TableIndex(name: 'item_title', columns: {#title})
class TodoItems extends Table {
IntColumn get id => integer().autoIncrement()();
TextColumn get title => text()();
TextColumn get content => text().nullable()();
IntColumn get categoryId => integer().references(TodoCategories, #id)();
TextColumn get generatedText => text().nullable().generatedAs(
title + const Constant(' (') + content + const Constant(')'))();
}
abstract class TodoCategoryItemCount extends View {
TodoItems get todoItems;
TodoCategories get todoCategories;
Expression<int> get itemCount => todoItems.id.count();
@override
Query as() => select([
todoCategories.name,
itemCount,
]).from(todoCategories).join([
innerJoin(todoItems, todoItems.categoryId.equalsExp(todoCategories.id))
]);
}
@DriftView(name: 'customViewName')
abstract class TodoItemWithCategoryNameView extends View {
TodoItems get todoItems;
TodoCategories get todoCategories;
Expression<String> get title =>
todoItems.title +
const Constant('(') +
todoCategories.name +
const Constant(')');
@override
Query as() => select([todoItems.id, title]).from(todoItems).join([
innerJoin(
todoCategories, todoCategories.id.equalsExp(todoItems.categoryId))
]);
}
@DriftDatabase(tables: [
TodoItems,
TodoCategories,
], views: [
TodoCategoryItemCount,
TodoItemWithCategoryNameView,
])
class Database extends _$Database {
Database(super.e);
@override
int get schemaVersion => 2;
@override
MigrationStrategy get migration {
return MigrationStrategy(
onCreate: (m) async {
await m.createAll();
// Add a bunch of default items in a batch
await batch((b) {
b.insertAll(todoItems, [
TodoItemsCompanion.insert(title: 'A first entry', categoryId: 0),
TodoItemsCompanion.insert(
title: 'Todo: Checkout drift',
content: const Value('Drift is a persistence library for Dart '
'and Flutter applications.'),
categoryId: 0,
),
]);
});
},
);
}
// The TodoItem class has been generated by drift, based on the TodoItems
// table description.
//
// In drift, queries can be watched by using .watch() in the end.
// For more information on queries, see https://drift.simonbinder.eu/docs/getting-started/writing_queries/
Stream<List<TodoItem>> get allItems => select(todoItems).watch();
}
Future<void> main() async {
// Create an in-memory instance of the database with todo items.
final db = Database(NativeDatabase.memory());
db.allItems.listen((event) {
print('Todo-item in database: $event');
});
// Add category
final categoryId = await db
.into(db.todoCategories)
.insert(TodoCategoriesCompanion.insert(name: 'Category'));
// Add another entry
await db.into(db.todoItems).insert(TodoItemsCompanion.insert(
title: 'Another entry added later', categoryId: categoryId));
final query = db.select(db.todoItems).join([
innerJoin(db.todoCategories,
db.todoCategories.id.equalsExp(db.todoItems.categoryId))
]);
for (final row in await query.get()) {
print('has row');
print(row.read(db.todoItems.categoryId));
print(row.read(db.todoCategories.name));
}
}