On Oct 4, 2011, at 9:37 AM, neurino wrote: > Hi Michael, > > the reason is Parent does not know its children until another relationship is > set (`id_str` in the code above). > > Consider this form validation part: > > if form.validate(): > user_strat = form.bind(UserStratigraphy()) > > I cannot bind prior creating an instance and this is quite a common situation. > > I can always go with manual adds of course but...
manual is never required for something that follows a repeatable rule - it's just mapper events are the worst place to do things, and yes, it has always been a restriction that the Session cannot be reliably manipulated from inside the flush procedure. You can add event listeners to the relationship in question using @validates, which then apply the corresponding extra objects. I'd still keep this at the object level. As a fallback, you'd hit it with the before_flush event. An eventual feature for "before_flush" is to break it into sub-events that can be limited to certain classes and statuses, but this is very easy to roll manually doing a simple "[obj for obj in session.dirty if isinstance(obj, MyClass)]" for now. -- 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.
