On 18/02/10 08:31, Sander wrote:
Can you explain yourself a little bit more about the other one to one
fields?
Well, django has a "OneToOneField" field type, that is like ForeignKey"
only assumes the two models are, well, one to one. And thus, the
generated reverse relation accessor returns a single object rather than
a set of objects, which is mildly convenient over being careful to keep
that true yourself. It was (and is) used to implement django's
multi-table inheritance. When you use that, there's an implicit
OneToOneField defined, basically.
http://docs.djangoproject.com/en/1.1/ref/models/fields/#onetoonefield
Until [mumble] ago, it also implied primary key as it was geared
towards inheritance.
class Student(models.Model):
user = models.OneToOneField(User, related_name="as_student")
class Teacher(models.Model):
user = models.OneToOneField(User, related_name="as_teacher")
u = User.objects.get(username='whatever')
Student.objects.create(user=u)
Teacher.objects.create(user=u)
u.as_student
u.as_teacher
This does mean Users can "be" both Students and Teachers, which you may
or may not want.
You have to define a signal handler to create UserProfiles if you want
them autocreated - so you can just as easily make the signal handler
create various other models with OneToOneFields if you want.
... So one advantage of multi-table-inheriting from (as Bruno
suggested) a profile (or indeed OneToOneField-ing to a created profile
rather than user which is highly similar) rather than doing that is that
it avoids "polluting" the namespace in User ("owned" by django, not
you...) with reverse relation accessors. OTOH it means every access
becomes that bit longer to write out, as you saw from Bruno's example.
... Just having the UserProfile mechanism as a "common idiom" might be
useful, as guide to people wanting to do "userprofiley things", and if
you're doing a "userprofiley thing", and _not_ using UserProfile, you
might be being needlessly obscure for developers joining your project...
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