How to write this "model" in Django?

Question

Hello,

I am currently using Django Users model. Very simple. However, I'd like to add one feature: Adding friends!

I would like to create 2 columns in my table:

UID (the ID of the User) friend_id (the ID of his friend! ...of course, this ID is also in Django's User model. The UID-friend_id combination must be unique! For example, if my ID is 84, I cannot have two rows the same, because I can only subscribe to the same friend once.

Can anyone tell me if this is the right way to do it? Should I do some KEY relationship for the "friend_id", or should I leave it like this, as "IntegerField"?

class Friend(models.Model):
    uid = models.ForeignKey(User)
    friend_id = models.IntegerField(default=0)

Thank you

Answer 1

You should create a model that defines the relationship between two users, and then define two foreign-key fields, each one to a User. You can then add a unique constraint to make sure you don't have duplicates.

There is a article here explaining exactly how to do this: http://www.packtpub.com/article/building-friend-networks-with-django-1.0

The example model from that page:

class Friendship(models.Model):
  from_friend = models.ForeignKey(
    User, related_name='friend_set'
  )
  to_friend = models.ForeignKey(
    User, related_name='to_friend_set'
  )
  def __unicode__(self):
    return u'%s, %s' % (
      self.from_friend.username,
      self.to_friend.username
    )
  class Meta:
    unique_together = (('to_friend', 'from_friend'), )