Thanks.. I think that will work.. will try it out shortly!
On Oct 8, 11:08 am, "Richard Dahl" <[EMAIL PROTECTED]> wrote:
> I have a model class 'Organization' with a parent and I do this with a
> method get_child_orgs:
>
> get_child_orgs(self):
> child_orgs = []
> co = Organization.objects.filter(parent__exact = self)
> for c in co:
> child_orgs.append(c)
> gc = c.get_child_orgs()
> child_orgs.extend(gc)
> return child_orgs
>
> On 10/8/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>
>
>
> > Ok..thanks.. I was afraid I was going to get that answer. If I do
> > this with select_related, I'm still going to have to implement a loop
> > to display them all in one list, because they'd come back as
> > company.parent_company.parent_company etc, instead of all in one top
> > level list... right?
>
> > On Oct 8, 9:19 am, Malcolm Tredinnick <[EMAIL PROTECTED]>
> > wrote:
> > > On Mon, 2007-10-08 at 13:13 +0000, [EMAIL PROTECTED] wrote:
> > > > In my model class I have:
>
> > > > class Company(models.Model):
> > > > company_id = models.AutoField(primary_key=True)
> > > > parent_company = models.ForeignKey("self",null=True)
> > > > .
> > > > .
>
> > > > How would I query to get back all children companies, as well as all
> > > > of their children companies, and their children companies, etc,
> > > > without writing a nested loop to do so?
>
> > > You can't do it with a general query because there's no way to do it in
> > > SQL with this data structure. The SQL has to do a join each time you
> > > query from parent back to child (or vice-versa), so we need to know the
> > > number of joins to create a query construction time.
>
> > > There is a "depth" parameter for select_related() queries that limits
> > > the number of recursion steps (otherwise infinite loops would result for
> > > queries like this) and you could use that to control the maximum number
> > > of children. However, I believe there are some bugs with it working for
> > > small values of depth (depth=1) and there might be others, so check the
> > > results carefully.
>
> > > Regards,
> > > Malcolm
--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---
