Simple JOIN in Django

Question

I'm trying to accomplish something akin to twitter on my website, where one user can follow another one. I want to select all User records that are following a User with a given ID. My follow relationship model look like:

class Following(models.Model):
  user = models.ForeignKey(User, related_name='is_following')
  followed = models.ForeignKey(User, related_name='is_followed')

And I'm using the django.contrib.auth.models User class.

Assuming I have a User object named "myUser" representing the followed person, what's the appropriate query to get everyone following them?

Answer 1

That's where the related_name attribute comes into play -- it allows you to follow a relationship backwards. So, to get all the users following a particular user, you'd use my_user.is_followed.

Obviously you might want to rename your attributes to reflect these relationships, since followed and is_followed might be a bit confusing, but that's how you'd do it.

Answer 2

mipadi's answer is missing '.all'.

In a view, the queryset

followers = my_user.is_followed.all()

returns a list of Following objects where my_user is being followed. To get the user that is following from a Following object f, use f.user

If followers is in the template context, you could do the following.

{% for f in followers %}

  {{ f.user }}

{% endfor %}

You might find the Django documentation for many to many relationships useful.