Django: Two way one-to-one relationship. Chick or egg?

Question

What is the appropriate way to create an instance of the following two models

class Administrator(models.Model):
    user = models.OneToOneField(User, primary_key=True)
    account = models.ForeignKey(Account)

class Account(models.Model):
    owner = models.OneToOneField(Administrator)

Both require each other. An account cannot exist without a primary user (owner), and an administrator (which is what owner is) cannot exist without an account. Yes a general User object can exist on it's own but I can't wrap my brain around which of these should come first and how to implement that correctly. If I have to use blank=True on Administrator's account attribute I will, but is there a better way? Should I use a transaction to ensure one cannot exist without the other?

Answer 1

If two models exist such that each requires the other, they should usually be combined into a single model.

In any case there is probably a better way to structure the classes. Personally I would construct a UserProfile class as follows:

class UserProfile(models.Model):
    user = models.OneToOneField(User)
    administrator = models.BooleanField()

or possibly:

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

class AdministratorProfile(UserProfile):
    # attributes

or even:

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

class AdministratorProfile(models.Model):
    profile = models.OneToOneField(UserProfile)

any of these methods should work.

Answer 2

I'm not totally sure I fully understand the differences between Administrator, Account, and contrib.auth.User,

This feels like the is-a vs has-a discussion. It sounds like Administrator is a User (really, a UserProfile, for reasons peculiar to django), and Administrator has an Account. Accounts do not have anything, since they cannot both own and be owned.

This is like a bank account vs a bank customer. Bank customers own their accounts, not the other way around. On the other hand, bank accounts have a list, and that list is the bank customers that may use the account.