Question

I have two models: call them questions and answers:

class FacetQuestion(models.Model):
    the_question    = models.CharField(max_length=50)

class FacetAnswer(models.Model):
    question        = models.ForeignKey(FacetQuestion)
    display_order   = models.SmallIntegerField()
    the_answer      = models.CharField(max_length=1024)

I’d like to present all the questions and answers in one list, with the questions and answers ordered per my choosing:

Q1
  A1
  A2
  A3
Q2
  A10
  A9
  A4

Without creating n+1 database queries or creating silly looking templates.
That’s an easy join for a database guy like myself, but Toto informs us we’re not in SQL land anymore:

select title_short,answer_note from coat_facetquestion
join coat_facetanswer on (coat_facetanswer.question_id=coat_facetquestion.id)
order by coat_facetquestion.id,coat_facetanswer.display_order;

What’s the best way in Django, and what would the template look like?

<ul>
    {% for q in questions %}
    <li>{{ q.the_question }}</li>
        {% for a in q.FacetAnswers_set.all %}
            <li>{{ q.the_answer }}</li>
        {% endfor %}
    {% endfor %}
</ul>

I see an older module that’s a bit on track at django-batch-select. There’s also select_related() which feels like it must be the answer, but if so the documentation is not quite making that clear.

Answer 1

Based on searching other stack exchange answers: for dealing with the hierarchical data, the best seems to be http://django-mptt.github.com/django-mptt/

For simply reducing the number of queries select_related() is a great help.

For displaying the hierarchical result I have not yet found much.