I am currently building a Django app that requires two different user types and I know that storing authentication information across multiple models/tables is a bad idea.

As such, I have created a User model to handle the authentication information (username, password, etc.). I have then created two different models, one for the buyers and one for the sellers, each with their own unique fields and one-to-one relationship to the User model.

Now, I thought this would work, but the problem is that it is still possible for a different buyer and seller to have the same User relation. How can I prevent this and restrict the User model to only a single one-to-one relation?

CodePudding user response：

You can add that field to user model instead of your way, by doing that you can ensure one user can only have one type

CodePudding user response：

You can use unique_together to achieve your goal like this:

class Buyer(models.Model):
    user_id = models.ForeignKey(User, ...)
    id = models.AutoField(primary_key=True)
    
    class Meta:
        unique_together = ('id', 'user_id',)

class Buyer(models.Model):
    user_id = models.ForeignKey(User, ...)
    id = models.AutoField(primary_key=True)
    
    class Meta:
        unique_together = ('id', 'user_id',)

By this way, one Buyer is linked to only one user and one Seller is linked to only one user too.