On Mon, 2007-10-22 at 15:03 +0200, Thomas Güttler wrote: > Hi, > > since obj.delete() uses "on delete cascade", I want to see first > which instances still have a reference to obj (and would get deleted). > > I write this little helper. Comments welcome: > > def all_related_instances(instance): > """ > Return all instances which have a relation to this instance. > You can check this list before instance.delete(), since all returned > instances would get deleted, too (ON DELETE CASCADE) > """ > assert isinstance(instance, models.Model) > meta=instance._meta > related=[] > for related_object in > meta.get_all_related_objects()+meta.get_all_related_many_to_many_objects(): > attr = getattr(instance, related_object.get_accessor_name()) > related.extend(attr.all()) > return related
That would seem to only account for things that are directly attached to the current model, rather than more distant relations. Have a look at what Model._collect_sub_objects() does -- or call it directly -- to see how Django goes about collecting all the objects for deletion. That method is seeded with an empty SortedDict() from Model.delete(). Regards, Malcoml -- Depression is merely anger without enthusiasm. http://www.pointy-stick.com/blog/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
