How to specify Parent-Child relationship within one Model?

Question

For example I have following code:

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

And I have following situations:

Answer 1

You can do this with a simple ForeignKey to self to indicate the parent:

parent = models.ForeignKey('self', blank=True, null=True, related_name='children')

Now you can do a2.parent = a1, and will automatically get access to a1.children.all().