@Entity(tableName = "users") public class User { @PrimaryKey @ColumnInfo(name = "user_id") public int userId; @ColumnInfo(name = "user_name") public String userName; } @Dao public interface UserDao { @Insert void insert(User user); @Query("SELECT * FROM users") List<User> getAllUsers(); } @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract UserDao userDao(); } AppDatabase db = Room.databaseBuilder(getApplicationContext(), AppDatabase.class, "my-database").build();