Entity list relationships in Android Room

I think that TypeConverter only works for static methods. I say this based on the example from here and here

From the relationships section here:

"Because SQLite is a relational database, you can specify relationships between objects. Even though most ORM libraries allow entity objects to reference each other, Room explicitly forbids this."

So I guess it's best if you add @Ignore on your locales property and make a method on RoomLocaleDao thats insert List<Locale> and call it after insert Region.

The method that inserts a Region can return the inserted id.

If the @Insert method receives only 1 parameter, it can return a long, which is the new rowId for the inserted item. If the parameter is an array or a collection, it should return long[] or List instead. (https://developer.android.com/topic/libraries/architecture/room.html#daos-convenience)