Do I also need to use select_related() anywhere?
On May 22, 5:57 pm, Alex Gaynor <alex.gay...@gmail.com> wrote:
> On Fri, May 22, 2009 at 7:41 PM, George Song <geo...@damacy.net> wrote:
>
> > On 5/22/2009 5:31 PM, Patrick wrote:
> > > What is the best way to make queries on a manytomany table?
>
> > > Given the models below, how can I get a list of all the songs a
> > > particular artist has?
>
> > > class Artist(models.Model):
> > > name = models.CharField(max_length=128)
>
> > > def __unicode__(self):
> > > return u'%s' %(self.name)
>
> > > class Album(models.Model):
> > > title = models.CharField(max_length=128)
> > > artists = models.ManyToManyField(Artist)
>
> > > def __unicode__(self):
> > > return u'%s' %(self.title)
>
> > > class Song(models.Model):
> > > title = models.CharField(max_length=128)
> > > albums = models.ManyToManyField(Album)
>
> > > def __unicode__(self):
> > > return self.title
>
> > Probably a compound query:
>
> > 1. All albums for a given artist
> > 2. All songs where albums in #1
>
> > --
> > George
>
> Song.objects.filter(albums__artists=<some_artist_obj_or_pk>) will do what
> you want.
>
> You might need to put distinct on this to prevent duplicate items.
>
> 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
-~----------~----~----~----~------~----~------~--~---
