@Override
      public void createAllTables(SupportSQLiteDatabase _db) {
        _db.execSQL("CREATE TABLE IF NOT EXISTS `tracking_events` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `event_data` TEXT NOT NULL)");
        _db.execSQL("CREATE  INDEX `index_tracking_events_id` ON `tracking_events` (`id`)");
        _db.execSQL("CREATE TABLE IF NOT EXISTS `items` (`id` INTEGER NOT NULL, `json` TEXT NOT NULL, `expires_at` INTEGER NOT NULL, PRIMARY KEY(`id`))");
        _db.execSQL("CREATE  INDEX `index_items_id` ON `items` (`id`)");
        _db.execSQL("CREATE TABLE IF NOT EXISTS `feedbacks` (`id` INTEGER NOT NULL, `json` TEXT NOT NULL, `owner_id` INTEGER NOT NULL, PRIMARY KEY(`id`))");
        _db.execSQL("CREATE UNIQUE INDEX `index_feedbacks_id` ON `feedbacks` (`id`)");
        _db.execSQL("CREATE  INDEX `index_feedbacks_owner_id` ON `feedbacks` (`owner_id`)");
        _db.execSQL("CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)");
        _db.execSQL("INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, \"e250e1d697c3932132e8d387acdd6341\")");
      }

      @Override
      public void dropAllTables(SupportSQLiteDatabase _db) {
        _db.execSQL("DROP TABLE IF EXISTS `tracking_events`");
        _db.execSQL("DROP TABLE IF EXISTS `items`");
        _db.execSQL("DROP TABLE IF EXISTS `feedbacks`");
      }