Thanks for your reply, Daniel. I didn't give my example specifically enough. In my particular case I actually have a handle to the Person and actually don't need all the join dates for all the people in that group. I just need that person's join date.
I can see that it is easy to get all membership info for a given group, but I'm guessing that my original solution is the appropriate solution for getting the join date for just a single person? Margie On Feb 16, 2:05 am, Daniel Roseman <dan...@roseman.org.uk> wrote: > On Wednesday, February 16, 2011 12:36:49 AM UTC, Margie Roginski wrote: > > > Say I am using an intermediary model like that in the doc: > > > class Person(models.Model): > > name = models.CharField(max_length=128) > > > class Group(models.Model): > > name = models.CharField(max_length=128) > > members = models.ManyToManyField(Person, through='Membership') > > > class Membership(models.Model): > > person = models.ForeignKey(Person) > > group = models.ForeignKey(Group) > > date_joined = models.DateField() > > > For a given group, say I want to go through the persons in the group > > and print the date each joined the group. > > > beatles = Group.objects.get(name="beatles") > > for person in group.members.all(): > > # get join date for person > > > What's the best way to do this? It seems to me that I have to add a > > related_name to the person field of Membership like this: > > > person = models.ForeignKey(Person, related_name="memberships") > > > and then traverse backward from the person back to the membership, > > filtering to find the correct membership based on the group name. Can > > someone tell me if there is a better way? So I'm thinking I have to > > do this: > > > beatles = Group.objects.get(name="beatles") > > for person in group.members.all(): > > joinDate = person.memberships.filter(group_name="beatles") > > [0].date_joined > > > Thanks for any pointers, > > > Margie > > It's easier than that. You can get all memberships for a group in one go: > > memberships = > Membership.objects.filter(group__name="beatles").select_related() > for m in memberships: > print m.person.name, m.date_joined > > -- > DR. -- 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.
