Den 13/03/2014 kl. 06.34 skrev Santiago Palacio Gómez <spala...@gmail.com>:
> Hi everyone,
>
> I'm a Django newbie, and I was following the tutorial for 1.6, creating a new
> app where one of the models is self-referencing. They ask to, in manage.py
> shell, create an instance of the model. But, as my model has a self reference
> foreign key, I can't pass any object to the key. I also would not like to
> leave it Nullable, as it may cause errors. Rather, I'd just like to pass
> 'self' as the reference, this is, the key it references should be its self
> key.
>
> Is it possible? Thanks in advance!
What is meant in the tutorial is most definitely not that the model 'instance'
should reference itself, but rather that the instance should reference another
instance of the same type, i.e. a parent-child relationship. Something like:
class Person(models.Model):
mother = models.ForeignKey('self', null=True)
father = models.ForeignKey('self', null=True)
You need to keep the field nullable because something must be root of the
relationship structure (unless you want to create only cyclic relationships,
which is not recommended for family structures...). To create a relationship do
this:
eve = Person.objects.create()
adam = Person.objects.create()
abel = Person.objects.create(mother=eve, father=adam)
Erik
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