android - How to migrate existing SQLite application to Room Persistance Library?

Question

It might be a bit early to ask, but is it possible and how to migrate/upgrade an existing SQLite database application to a new Android Room Persistance Library?

Answer 1

Assuming your room entities match your current table schemas, you can keep using the same database/tables.

Room manages a master table which is initialized on creation or upgrade of the database, so you need to increment your database version and provide a dummy migration:

@Database(entities = SomeEntity.class, version = EXISTING_VERSION + 1)
public class MyDatabase extends RoomDatabase {
    // ...
}

MyDatabase db = Room.databaseBuilder(context, MyDatabase.class, "db_name")
                    .addMigrations(new Migration(EXISTING_VERSION, EXISTING_VERSION + 1) {
                        @Override
                        public void migrate(SupportSQLiteDatabase database) {
                            // NOOP
                        }
                    }).build();