SQLAlchemy many-to-many relationship updating association object with extra column

flask sqlalchemy many-to-many flask-sqlalchemy

You get an integrity error because you are trying to create a new object with the same primary keys.

This:

a = Set_Product_Association(set=s, product=p, quantity=43)

Does not update, but create.

If you want to update the actual row in the table, you need to update the existing one:

assoc = Set_Product_Association.query.filter_by(set=s, product=p).first()assoc.quantity = 43db.session.commit()

Also, from the documentation it is advised to not use a model but an actual table.

CodeHunter