Let me be more clear. Partial objects, such as a book with an author created from a user request may or may not have DB ids that may or may not exist. If you

Let me be more clear. Partial objects, such as a book with an author created from a user request may or may not have DB ids that may or may not exist. If you want to add a Book object with an Author you must first upsert the Author to possibly retrieve the DB id which already exists and cannot simply be generated locally. This can often be a bit confusing or cumbersome compared to the SQL. Why are you caring about DB ids if the ORM is supposed to handle it, asks OP.