python - Django: Why do some model fields clash with each other?

Question

I want to create an object that contains 2 links to Users. For example:

class GameClaim(models.Model):
    target = models.ForeignKey(User)
    claimer = models.ForeignKey(User)
    isAccepted = models.BooleanField()

but I am getting the following errors when running the server:

• Accessor for field 'target' clashes with related field 'User.gameclaim_set'. Add a related_name argument to the definition for 'target'.

• Accessor for field 'claimer' clashes with related field 'User.gameclaim_set'. Add a related_name argument to the definition for 'claimer'.

Can you please explain why I am getting the errors and how to fix them?

Answer 1

You have two foreign keys to User. Django automatically creates a reverse relation from User back to GameClaim, which is usually gameclaim_set. However, because you have two FKs, you would have two gameclaim_set attributes, which is obviously impossible. So you need to tell Django what name to use for the reverse relation.

Use the related_name attribute in the FK definition. e.g.

class GameClaim(models.Model):
    target = models.ForeignKey(User, related_name='gameclaim_targets')
    claimer = models.ForeignKey(User, related_name='gameclaim_users')
    isAccepted = models.BooleanField()