Initialization data problem

[xqa]

I want to use a database with initial data and will add other tables，but I can't use other tables, this gives an error Unhandled Exception: SqliteException(1): no such table: todos, SQL logic error (code 1).

Is there any other way to import data?

@DriftDatabase(tables: [Todos])
class AppDb extends _$AppDb {
  AppDb() : super(_openConnection());

  @override
  int get schemaVersion => 1;

  Future<int> addTodo(TodosCompanion entry) {
    return into(todos).insert(entry);
  }
}

// LazyDatabase _openConnection() {
//   return LazyDatabase(() async {
//     final dbFolder = await getApplicationDocumentsDirectory();
//     final file = File(p.join(dbFolder.path, 'db.sqlite'));
//     return NativeDatabase(file);
//   });
// }

LazyDatabase _openConnection() {
  return LazyDatabase(() async {
    final dbFolder = await getApplicationDocumentsDirectory();
    final file = File(p.join(dbFolder.path, 'app.sqlite'));

    if (!await file.exists()) {
      final blob = await rootBundle.load('assets/db.sqlite');
      final buffer = blob.buffer;
      await file.writeAsBytes(buffer.asUint8List(blob.offsetInBytes, blob.lengthInBytes));
    }

    return NativeDatabase(file);
  });
}

class Todos extends Table {
  IntColumn get id => integer().autoIncrement()();

  TextColumn get title => text()();

  TextColumn get des => text()();

  BoolColumn get finish => boolean().withDefault(const Constant(false))();
}

[simolus3]

So I assume that your assets/db.sqlite does not contain all of the tables that you have defined in your database schema? The easiest way to fix that would be to just add them. If that is not possible, I'd reserve a low schema version number just for the asset so that this can be recognized by drift when opening the database.

So, I would set the schema version in assets/db.sqlite to 1 (open it with sqlite3 assets/db.sqlite and run pragma user_version = 1).

Then, you set the schemaVersion getter in your database class to 2 and write a migration to add the missing tables:

  @override
  MigrationStrategy get migration {
    return MigrationStrategy(
      onUpgrade: (Migrator m, int from, int to) async {
        if (from < 2) {
          // Probably coming from the asset, add missing tables
          await m.createAll();
        }

        // perhaps other migrations to be added in the future
      },
    );
  }

[xqa]

Thanks, this solved my problem