Question

I’m trying to make a simple ‘follow’ functionality in Django, like so (by the way, I’m not using django.contrib.auth, if that makes a difference):

class User(models.Model):
     followers = models.ManyToManyField('self')
     # rest of code

I’ve tested this out on my site with two users, User X and User Y…but when User X is added to User Y’s followers, User Y is also added to User X’s followers, which was not the intended outcome. How can I make this a one-sided relationship? Am I doing something wrong?

Answer 1

By default, a self referential ManyToManyField is symmetrical. See the following in the docs:

…ManyToManyField is assumed to be symmetrical — that is, if I am your
friend, then you are my friend.

If you do not want symmetry in many-to-many relationships with self,
set symmetrical to False. This will force Django to add the descriptor
for the reverse relationship, allowing ManyToManyField relationships
to be non-symmetrical.

You can achieve it by adding:

models.ManyToManyField("self", symmetrical=False)