flutter-drift（Flutter drift 搜索）

Flutter Drift

Comprehensive guide for using drift database library in Flutter applications.

Overview

Flutter Drift skill provides complete guidance for implementing persistent local storage in Flutter apps using the drift library. Drift is a reactive persistence library for Flutter built on SQLite, offering type-safe queries, auto-updating streams, schema migrations, and cross-platform support.

Quick Start

Add dependencies to pubspec.yaml:

dependencies:
  drift: ^2.30.0
  drift_flutter: ^0.2.8
  path_provider: ^2.1.5

dev_dependencies:
  drift_dev: ^2.30.0
  build_runner: ^2.10.4

Define database:

@DriftDatabase(tables: [TodoItems])
class AppDatabase extends _$AppDatabase {
  AppDatabase([QueryExecutor? e])
      : super(
          e ??
              driftDatabase(
                name: 'app_db',
                native: const DriftNativeOptions(
                  databaseDirectory: getApplicationSupportDirectory,
                ),
                web: DriftWebOptions(
                  sqlite3Wasm: Uri.parse('sqlite3.wasm'),
                  driftWorker: Uri.parse('drift_worker.js'),
                ),
              ),
        );

  @override
  int get schemaVersion => 1;
}

Run code generator:

dart run build_runner build

Reference Files

See detailed documentation for each topic:

• setup.md - Flutter-specific setup with drift_flutter
• tables.md - Table definitions, columns, constraints
• queries.md - SELECT, WHERE, JOIN, aggregations
• writes.md - INSERT, UPDATE, DELETE, transactions
• streams.md - Reactive stream queries
• migrations.md - Database schema migrations
• flutter-ui.md - Flutter UI integration patterns

Common Patterns

Reactive Todo List with StreamBuilder

class TodoList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final database = Provider.of<AppDatabase>(context);

    return StreamBuilder<List<TodoItem>>(
      stream: select(database.todoItems).watch(),
      builder: (context, snapshot) {
        final todos = snapshot.data ?? [];
        return ListView.builder(
          itemCount: todos.length,
          itemBuilder: (context, index) {
            final todo = todos[index];
            return ListTile(
              title: Text(todo.title),
              trailing: Checkbox(
                value: todo.isCompleted,
                onChanged: (value) {
                  database.update(database.todoItems).replace(
                    TodoItem(
                      id: todo.id,
                      title: todo.title,
                      isCompleted: value ?? false,
                    ),
                  );
                },
              ),
            );
          },
        );
      },
    );
  }
}

Add Item with Form

Future<void> showAddTodoDialog(BuildContext context) async {
  final controller = TextEditingController();
  final database = Provider.of<AppDatabase>(context);

  await showDialog(
    context: context,
    builder: (context) {
      return AlertDialog(
        title: const Text('Add Todo'),
        content: TextField(
          controller: controller,
          decoration: const InputDecoration(labelText: 'Title'),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () async {
              if (controller.text.isNotEmpty) {
                await database.into(database.todoItems).insert(
                  TodoItemsCompanion.insert(title: controller.text),
                );
                if (context.mounted) {
                  Navigator.pop(context);
                }
              }
            },
            child: const Text('Add'),
          ),
        ],
      );
    },
  );

  controller.dispose();
}

Provider Setup

final databaseProvider = Provider<AppDatabase>((ref) {
  final database = AppDatabase();
  ref.onDispose(database.close);
  return database;
});

Database Migration

@override
MigrationStrategy get migration {
  return MigrationStrategy(
      onUpgrade: stepByStep(
        from1To2: (m, schema) async {
          await m.addColumn(schema.todoItems, schema.todoItems.dueDate);
        },
      ),
    );
}

Platform-Specific Setup

Mobile (Android/iOS/macOS/Windows/Linux)

Uses drift_flutter with getApplicationSupportDirectory.

Web

Place sqlite3.wasm and drift_worker.js in web/ folder.

Isolate Sharing

AppDatabase.defaults(): super(
  driftDatabase(
    name: 'app_db',
    native: DriftNativeOptions(
      shareAcrossIsolates: true,
    ),
  ),
);

Testing

Use in-memory database for tests:

AppDatabase createTestDatabase() {
  return AppDatabase(NativeDatabase.memory());
}

Best Practices

1. Use drift_flutter for easy database setup across platforms
2. StreamBuilder for reactive UI updates
3. Provider/Riverpod for database access management
4. Close database on app/widget dispose
5. Use migrations when schema changes
6. Index columns used in WHERE clauses
7. Limit stream query size for performance
8. Use transactions for multi-step operations
9. Debounce user input for search/filter
10. Handle loading/error states in UI

Troubleshooting

Build Fails

dart run build_runner clean
dart run build_runner build --delete-conflicting-outputs

Migration Errors

dart run drift_dev schema validate
dart run drift_dev make-migrations

Stream Not Updating

Ensure operations go through drift APIs, not raw SQLite.