On 3/18/06, Ned Batchelder <[EMAIL PROTECTED]> wrote:
> I want to select objects based on their relationships with related
> objects, but I don't seem to be able to do it, because I'm trying to use
> a foreign key in the "wrong" direction. For example, in the Polls and
> Choices model, I can do this (from the docs):
>
> choices.get_list(poll__slug__exact="eggs")
>
> This works because the Choice class has a poll ForeignKey. But I can't
> get a list of polls based on the characteristics of choices:
>
> polls.get_list(choice__choice__exact="overeasy") # Doesn't work.
>
> Am I wrong? Please tell me there is a way to accomplish what I want.
Here's how I'd solve this particular problem:
[c.get_poll() for c in choices.get_list(choice__exact='foo')]
If you need to remove duplicates:
dict([(c.get_poll(), 1) for c in
choices.get_list(choice__exact='foo')]).keys()
(The second example exploits the fact that dictionaries can't have
duplicate keys.)
The database API doesn't support this kind of "reverse" lookup in 0.91.
Hope this helps!
Adrian
--
Adrian Holovaty
holovaty.com | djangoproject.com
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