Circular dependencies *shouldn't* be a problem on PostgreSQL because all constraints are set DEFERABLE INITIALLY DEFERRED; that means no constrain checks should be performed are performed until the transaction boundary, so all circular references shouldn't be a problem.
Ticket #3615 exists because MySQL's implementation of DEFERABLE INITIALLY DEFERRED under InnoDB is, to use the technical term, "Broken". It's unrelated to any problem you may have found in PostgreSQL, because PostgreSQL gets the underlying behaviour right. Beyond that, we need a specific test case to take this any further. As it stands, I'm not aware of any problems loading fixtures into PostgreSQL. If you are able to construct and provide a set of models (which you have done) and simple fixture (which you haven't) that fails reliably, we have a new bug on our hands, and you should open a ticket with all the details you can provide. Confirming whether this is a problem with the alpha, or an ongoing problem would also be helpful. Yours, Russ Magee %-) On Mon, Jun 17, 2013 at 6:22 AM, Yo-Yo Ma <baxterstock...@gmail.com> wrote: > There doesn't appear to be a way to load fixtures from JSON (using > Postgres - works fine in sqlite3) for the following models: > > > class Collection(models.Model): > main_thing = models.OneToOneField( > 'things.Thing', > null=True, > on_delete=models.SET_NULL > ) > > class Thing(models.Model): > collection = models.ForeignKey( > 'collections.Collection' > ) > > > Here is the exception: > > Problem installing fixture 'my_fixture.json': Could not load > collections.Collection(pk=1): insert or update on table > "collections_collection" violates foreign key constraint > "main_thing_id_refs_id_3a4d3fef" > DETAIL: Key (main_thing_id)=(1) is not present in table "things_thing". > > I'm not sure if the issue is due to the unique constraint implied by a > OneToOneField, or if it's just related to this issue: > https://code.djangoproject.com/ticket/3615 (seems like that ticket and > related ones have been closed for years, so possibly not related). > > Any thoughts? > > Note: I'm using @1.6a1 > > -- > You received this message because you are subscribed to the Google Groups > "Django developers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to django-developers+unsubscr...@googlegroups.com. > To post to this group, send email to django-developers@googlegroups.com. > Visit this group at http://groups.google.com/group/django-developers. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "Django developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at http://groups.google.com/group/django-developers. For more options, visit https://groups.google.com/groups/opt_out.
