Check if OneToOneField is None in Django

Question

I have two models like this:

class Type1Profile(models.Model):
    user = models.OneToOneField(User, unique=True)
    ...


class Type2Profile(models.Model):
            


        

Answer 1

in case you have the Model

class UserProfile(models.Model):
    user = models.OneToOneField(User, unique=True)

And you just need to know for any User that UserProfile exists/or not - the most efficient way from the database point of view to use exists query.

Exists query will return just boolean, rather than reverse attribute access like hasattr(request.user, 'type1profile') - which will generate get query and return full object representation

To do it - you need to add a property to the User model

class User(AbstractBaseUser)

@property
def has_profile():
    return UserProfile.objects.filter(user=self.pk).exists()