I assume that you are talking about the select_related() and prefetch_related() queryset methods?
https://docs.djangoproject.com/en/1.7/ref/models/querysets/#select-related https://docs.djangoproject.com/en/1.7/ref/models/querysets/#prefetch-related Both of those sections have excellent examples, and detail what the differences are (primarily joins vs. separate queries, respectively). For better help, you'll need to go into more detail about the queries you are trying to make, what you've tried (with code examples if possible), and the results/errors you are seeing. In general, I would try to get an initial queryset working and gathering the correct results first before looking at optimizations such as select_related(). Any sort of pre-fetching will only confuse the situation if the base queryset is incorrect. -James On Wed, Feb 25, 2015 at 12:05 PM, cool-RR <ram.rac...@gmail.com> wrote: > Hi guys, > > I'm trying to solve a problem using the new `Prefetch` but I can't figure > out how to use it. > > I have these models: > > class Desk(django.db.models.Model): > pass > > class Chair(django.db.models.Model): > desk = django.db.models.Foreignkey('Desk', related_name='chair',) > nearby_desks = django.db.models.ManyToManyField( > 'Desk', > blank=True, > ) > > I want to get a queryset for `Desk`, but it should also include a > prefetched attribute `favorite_or_nearby_chairs`, whose value should be > equal to: > > Chair.objects.filter( > (django.db.models.Q(nearby_desks=desk) | > django.db.models.Q(desk=desk)), > some_other_lookup=whatever, > ) > > Is this possible with `Prefetch`? I couldn't figure out how to use the > arguments. > > > Thanks, > Ram. > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to django-users+unsubscr...@googlegroups.com. > To post to this group, send email to django-users@googlegroups.com. > Visit this group at http://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/46d9fdb7-c008-4496-acda-ac7cb30b4a89%40googlegroups.com > <https://groups.google.com/d/msgid/django-users/46d9fdb7-c008-4496-acda-ac7cb30b4a89%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at http://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CA%2Be%2BciVk7_6VBDoBE-qjLBwrBxiNeVdP6-fwwnOXV%3DvSA3HnCw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
