Thanks a lot, Atilla.
`Question.objects.filter(answer__user=user).distinct()` returns
exactly what I expect. This is wonderful, thanks a lot. I also
recheck the django manual and found this solution has a name as "query
over related objects" (http://www.djangoproject.com/documentation/
db_api/#queries-over-related-objects). This is really powerful yet
simple enough.
Alex
On Mar 9, 12:56 am, Atilla <[EMAIL PROTECTED]> wrote:
> On 08/03/07, Alex Dong <[EMAIL PROTECTED]> wrote:
>
>
>
>
>
> > Hi all,
>
> > I have a data model like this:
> > * a `user` has multiple `questions`
> > * a `user` could give multiple `answer`s or `comment`s to any
> > `question`s.
> > So here, there are
> > * a one-to-many relationship from `user` to `question`
> > * a many-to-many relationship between `question` and `answer`,
> > `question` and `comment`.
> > Now I need to pull out a list of all the questions a given user has
> > either answered or commented on. I could do `user.question_set` or
> > `user.answer_set`.
>
> > Now if I write a template like this:
> > ` {% for answer in user.answer_set %}
> > ... {{ answer.question. ... }}
> > {% endfor %}
> > `
> > I could end up with showing the same questions many times.
>
> > I know for sure that this task is not that difficult if I retreat to
> > using `JOIN` and use raw sql for my query. But I'm wondering does
> > Django offers a neat solution for this question without using raw
> > sql?
>
> > Thanks,
> > Alex
>
> How about this: Question.objects.filter(answer__user_id=userID) - this
> should give you the question objects for which the user has given
> answers. Extend the filter with a Q clause to do the OR for comments.
> You may need to throw a .distinct() in there as well. I've got a
> similar thing that works, I'm just not sure about the exact syntax for
> your case.
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