On Jul 21, 3:35 pm, Conor <conor.edward.da...@gmail.com> wrote: > > It means that there is a Child row already in the database with > parent_id=1234. When you reassign p.children to not include that child, > SQLAlchemy detects that the child object is now an orphan (has no > parent). Based on your cascade rules (cascade="all"), SQLAlchemy will > try to NOT delete the child, but instead set its parent_id to NULL (the > only sensible alternative to not deleting the child). > > If you want the child to be deleted in this case, change the cascade to > "all,delete-orphan". Otherwise, you need to ensure that the child is > kept in p.children, e.g. p.children += [Child(details=x) for x in x_list].
Aah, thank you. That appears to have been exactly the problem. It's hard to find many examples of working with objects like this in the docs so I wasn't sure how to delete the old list and replace it with a new list. It looks like the cascade="all,delete-orphan" is the right thing to do for all ownership relations. -- Ben Sizer -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
