On 18.06.2009 14:05, Ramiro Morales wrote: > > Why do you thing there should be a automatically created one to one > relationship from Customer to Contact named "contact"?.
Why I think there should be a automatic one-to-one relation from Customer to Contact? Because that's what the MTI documentation says (as far as I understand it): > Specifying the parent link field > > As mentioned, Django will automatically create a OneToOneField > linking your child class back any non-abstract parent models. If you > want to control the name of the attribute linking back to the parent, > you can create your own OneToOneField and set parent_link=True to > indicate that your field is the link back to the parent class. http://docs.djangoproject.com/en/dev/topics/db/models/#specifying-the-parent-link-field It's true that I didn't notice that the example (http://www.djangoproject.com/documentation/models/one_to_one/) isn't about MTI at all (rather a kind of emulation). Okay, when I add an explicit parent link in my example: contact = models.OneToOneField(contacts.Contact,parent_link=True) then the TypeError disappears. But still I would now expect that the following works: >>> c = Customer(contact=luc) >>> c.save() >>> c.last_name Saffre But it fails, saying: Failed example: c.last_name Expected: Saffre Got: '' It looks as if Django doesn't "copy" the values of the existing Contact into the Customer. The last_name field was inherited (it didn't say "AttributeError: 'Customer' object has no attribute 'last_name'") but it is empty. Note that I'm using Django development version, revision 11066... I guess that this is a bug and that it has to do with ticket #7623 (http://code.djangoproject.com/ticket/7623). Thus cc to django-developers and a new very short example showing the problem. (Should I wait for feedback from developers before opening a new ticket?) Luc --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
""" Small example for the problem described in ticket #7623 (http://code.djangoproject.com/ticket/7623) With revision 11066, the following doctest fails:: Failed example: r Expected: <Restaurant: Demon Dogs> Got: <Restaurant: > >>> p1 = Place(name='Demon Dogs') >>> p1.save() # Create a Restaurant from this Place. >>> r = Restaurant(place=p1, serves_hot_dogs=True) >>> r.save() >>> r <Restaurant: Demon Dogs> """ from django.db import models class Place(models.Model): name = models.CharField(max_length=50) def __unicode__(self): return self.name class Restaurant(Place): serves_hot_dogs = models.BooleanField() # the following explicit parent_link should not be necessary according to # http://docs.djangoproject.com/en/dev/topics/db/models/#specifying-the-parent-link-field place = models.OneToOneField(Place,parent_link=True)
