On Thu, Feb 5, 2009 at 3:24 PM, George Sakkis <george.sak...@gmail.com>wrote:
> > On Feb 5, 3:13 pm, Alex Gaynor <alex.gay...@gmail.com> wrote: > > On Thu, Feb 5, 2009 at 3:09 PM, George Sakkis <george.sak...@gmail.com > >wrote: > > > > > > > > > > > > > Hello, > > > > > I am looking at the raw sql executed when I run a delete or update on > > > a QuerySet and it appears that it does a redundant "select *" for the > > > queryset before the actual delete/update. For example > > > > > delete_ids = (108, 107, 106) > > > qs = MyModel.objects.filter(pk__in=delete_ids) > > > print connection.queries # shows no queries > > > qs.delete() > > > print connection.queries # shows two queries, a select followed by a > > > delete > > > > > Am I missing something or Is this supposed to work like this, and if > > > so why ? > > > > > George > > > > No you are correct, and this intended behavior. This is because Django > > emulates the CASCADE behavior for DBs which don't support it, so it needs > to > > build up the list of related objects internally, to do this it needs the > > objects themselves. > > > > To get a better idea of what I'm describing take a look at the source: > http://code.djangoproject.com/browser/django/trunk/django/db/models/q... > > Thanks, that was quick! Ok, this clears up things, though I'm > wondering if it could be smarter and check if there are no related > objects based on the schema alone, and if that's the case avoid the > redundant select. I can open a feature request ticket If that makes > sense. > > George > > > Yes, feel free to do this, I can't say whether or not it would be accepted or not(I'm not a core dev) but it's certainly something for consideration. Alex -- "I disapprove of what you say, but I will defend to the death your right to say it." --Voltaire "The people's good is the highest law."--Cicero --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
