Question

I am building a forum application for a website and have a “quote_id” column in the Posts table to put in a post_id if someone quotes a certain post to reply to. That is part of the Posts table just like all other posts. However, when I retrieve all records that match the topic that corresponds to the topic chosen, there will be a few that quote other posts. I cannot seem to find a way to do this in Django ORM to retrieve the quoted posts info to display along with the post that quoted it(to display within the post that quoted it). What I have so far is below:

def show_topic_posts(request,forum_id,topic_id):
    posts = Post.objects.filter(topic_id=topic_id)
    topic = Topic.objects.get(topic_id=topic_id)
    context = RequestContext(request,{'posts':posts,'topic':topic})
    return render_to_response('forums/topics_posts.html',context_instance=context)

class Post(models.Model):
    post_id = models.AutoField(primary_key=True)
    forum_id = models.ForeignKey(Forum)
    topic_id = models.ForeignKey(Topic)
    post_date_time = models.DateTimeField(auto_now=True)
    post_user_id = models.ForeignKey(User)
    post_quote_id = models.IntegerField(null=True,blank=True)
    post_body = models.TextField()
    post_likes = models.IntegerField(default=0)
    post_is_flagged = models.BooleanField(default=False)

def __unicode__(self):
    return '%i' % self.topic_id

def get_absolute_url(self):
    return '/forums/%s/%s/%s/' % (str(self.forum_id.pk), str(self.topic_id.pk),self.topic_id)

How in the world can I do this? Ive searched Google and Django Book and Django website trying to find a way to do this. Thanks!

Answer 1

Drop the post_quote_id field and create a recursive m2m-relationship for your Post model.

quoted_by = models.ManyToManyField('self')

That way posts can refer to other posts and you should be able to easily fetch the related posts for all your posts matching a certain topic.

example_post = Post.objects.get(pk=1)
posts_that_quote_my_example_post = example_post.quoted_by.all()

And in your template you could fetch the posts that quote a specific post like this:

<ul>
  {% for quote in post.quoted_by.all %}
    <li>{{ quote.post_body }}</li>
  {% endfor %}
</ul>

If you want to additionally store the person that quoted a certain post you’ll need to add an intermediary model using the through parameter.