On Tue, Apr 14, 2009 at 6:00 PM, gordyt <gor...@gmail.com> wrote:
>
> I think I've tracked down the problem. Here is a bit of code from
> django.db.models.fields.related.py:
>
> def get_db_prep_lookup(self, lookup_type, value):
> # If we are doing a lookup on a Related Field, we must be
> # comparing object instances. The value should be the PK of
> value,
> # not value itself.
> def pk_trace(value):
> # Value may be a primary key, or an object held in a
> relation.
> # If it is an object, then we need to get the primary key
> value for
> # that object. In certain conditions (especially one-to-
> one relations),
> # the primary key may itself be an object - so we need to
> keep drilling
> # down until we hit a value that can be used for a
> comparison.
> v, field = value, None
> try:
> while True:
> v, field = getattr(v, v._meta.pk.name), v._meta.pk
>
> except AttributeError:
> pass
> if field:
> if lookup_type in ('range', 'in'):
> v = [v]
> v = field.get_db_prep_lookup(lookup_type, v)
> if isinstance(v, list):
> v = v[0]
> # BEGIN (got)
> else:
> field = self.rel.get_related_field()
> if field:
> v = field.get_db_prep_lookup(lookup_type, v)
> # END (got)
> return v
>
> I added the part between BEGIN and END.
>
> The problem was that, for the child model in multi-table inheritance,
> its primary key in the database was being created by django as a
> OneToOneField (which is correct, of course), and it was creating the
> column using the proper type and everything, but you can see that
> without the little part that I added, the value was not being properly
> prepared for a lookup.
>
> --gordy
> >
>
Take a look at: http://code.djangoproject.com/ticket/10785
Alex
--
"I disapprove of what you say, but I will defend to the death your right to
say it." --Voltaire
"The people's good is the highest law."--Cicero
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