database_manager.dart

void insert(List<DatabaseModel> models) async {
    var db = await database;
    var batch = db.batch();
    for (var model in models) {
      DatabaseTable table = _tables[model.runtimeType];
      if (table == null) {
        return;
      }

      batch.insert(table.name, model.toMap());
    }
    await batch.commit();
  }
  
Future<List<Map>> fetchAllEntriesOf(Type type) async {
    DatabaseTable table = _tables[type];

    if (table == null) {
      return [];
    }

    var db = await database;
    var maps = await db.query(table.name, columns: table.columns);
    return maps;
  }