SQLAlchemy many-to-many orphan deletion

Question

I\'m trying to use SQLAlchemy to implement a basic users-groups model where users can have multiple groups and groups can have multiple users.

When a group becomes empty

Answer 1

I think you want cascade='save, update, merge, expunge, refresh, delete-orphan'. This will prevent the "delete" cascade (which you get from "all") but maintain the "delete-orphan", which is what you're looking for, I think (delete when there are no more parents).