Ah, glad to know that it is a known issue at least and not a new problem. Thanks for the info.
On Oct 29, 9:07 pm, Malcolm Tredinnick <[EMAIL PROTECTED]> wrote: > On Mon, 2007-10-29 at 20:58 +0000, Kevin wrote: > > I'm trying to figure out how to chain filters for a many-to-many > > relation ship that is evaluating to an empty set when it should not. I > > basically have some a test with multiple dimms. I want to find a test > > with both dimm "sizes" 1024 & 2048. > > > class TestLine(models.Model): > > #...some test info > > > class Dimm(models.Model): > > testline = models.ForeignKey(TestLine) > > size = models.IntegerField() > > > models.TestLine.objects.filter(dimm__size=1024).filter(dimm__size=2048) > > > This returns an empty set, but I know there is a test with multiple > > dimm objects and meets this criteria. Is there a limitation that I'm > > missing here? Is there an alternative method to accomplish the intent > > here? > > So I see you've found an alternative approach that works for now. The > underlying thing going on here is that there is a bug in the way Django > generates the SQL for many-to-many relations. If you try to filter on on > the same column more than once, it still only makes a single join to the > intermediary table, so you end up with things look like: > > ... where foo_id = 6 and foo_id = 7 ... > > which is clearly impossible to satisfy for a unique column on the same > table. > > This is ticket #1801 and has been fixed as part of the queryset-refactor > branch. When that work is complete, it'll be merged into trunk (the > branch is not suitable for testing yet) > > Regards, > Malcolm > > -- > Remember that you are unique. Just like everyone > else.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 -~----------~----~----~----~------~----~------~--~---
