SQLAlchemy: Using delete/update with a join query

Question

Using Flask-SQLAlchemy, I would like to delete rows in table Questions based on the values of another table which is linked to table Topic which then is linked to table Subject with foreign keys. I tried this query:

db.session.query(Questions).join(Topic)join(Subject).filter(Subject.account_id==current_user.id).delete()

However, I receive an error:

InvalidRequestError: Can't call Query.update() or Query.delete() when join(), outerjoin(), select_from(), or from_self() has been called

So from this I suppose I cannot use .delete() with .join()

Is there a workaround for this issue? Thanks.

Answer 1

You don't have to use join for your query, you may done it somehow like

db.session.query(Post).filter(Post.user_id==current_user.id).delete()

Assuming your Post have a user_id column.

Join tables would not know which table to delete, Post or User, because it actually have a convoluted middle table constructed, and query from it.