On Wed, 2007-10-31 at 23:05 -0400, George Vilches wrote: > Malcolm Tredinnick wrote: > >> > >> >>> Assembly.objects.select_related() > >> [<Assembly: Assembly object>, <Assembly: Assembly object>, <Assembly: > >> Assembly object>, <Assembly: Assembly object>, <Assembly: Assembly > >> object>, <Assembly: Assembly object>] > >> >>> len(Assembly.objects.select_related()) > >> 6 > >> >>> Assembly.objects.select_related().count() > >> 2L > >> > >> > >> Since I'm using select_related(), I would expect it to follow the INNER > >> JOINs to do the .count(). I can force it to use the JOINs by doing this: > > > > This is where you've made a mistake (aside from the to_field problem > > Karen pointed out). Your assumption is wrong. select_related() is only > > an optimisation as far as loading the data form the database. It should > > *never* change the result of a quantitative query like this. If it does, > > it would be a bug. > > > > Regards, > > Malcolm > > > > So is it expected behavior then that when I use filter criteria like this: > > >>> > Assembly.objects.select_related().filter(item_group__id__gte=-1).count() > 6L
Once again, the select_related() bit has nothing to do with it. The filter() call is dragging in the remote table. Filters have an effect on the result set, select_related() is just an optimisation that controls when the result set pieces are retrieved. Rather than addressing each of your questions one-by-one, since they're all of the same variety, I'll simply repeat that if including select_related() changes the result set, it's a bug. So you should try each of your queries with and without select_related() if you're in doubt. Regards, Malcolm -- He who laughs last thinks slowest. 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 django-users@googlegroups.com 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 -~----------~----~----~----~------~----~------~--~---
