On Jun 3, 5:59 pm, Don Spaulding <donspauldin...@gmail.com> wrote:
> On Jun 3, 5:22 pm, Don Spaulding <donspauldin...@gmail.com> wrote:
>
>
>
> > On Jun 3, 3:05 pm, Alex Gaynor <alex.gay...@gmail.com> wrote:
>
> > > On Wed, Jun 3, 2009 at 3:03 PM, Don Spaulding
> > > <donspauldin...@gmail.com>wrote:
>
> > > > bump.
>
> > > > Can anyone tell me if this looks like a bug in Django?
>
> > > > On Jun 1, 6:12 pm, Don Spaulding <donspauldin...@gmail.com> wrote:
> > > > > Hi all,
>
> > > > > I've got a quick use case that I think should work according to the
> > > > > docs, but it's not. In this case, Domain objects have a reverse fkey
> > > > > relation named "reports", and the Report model has an "updated"
> > > > > field. I'd like to annotate and order Domains by the max value of
> > > > > "updated" for all related reports. The following interactive session
> > > > > shows the behavior pretty well.
>
> > > > > >>> qs =
> > > > Domain.objects.annotate(last_updated=Max('reports__updated')).order_by('last_updated')
> > > > > >>> qs.count()
> > > > > 1577
> > > > > >>> print qs[0].last_updated
>
> > > > > IndexError: list index out of range>>> qs.count()
>
> > > > > InternalError: current transaction is aborted, commands ignored until
> > > > > end of transaction block
>
> > > > > >>> connection._rollback()
>
> > > > > If I drop off the order_by call, things appear to work again.
>
> > > > > >>> qs = Domain.objects.annotate(last_updated=Max('reports__updated'))
> > > > > >>> qs.count()
> > > > > 1577
> > > > > >>> print qs[0].last_updated
>
> > > > > 2009-05-28 13:25:55.027600
>
> > > > > What am I missing here (besides a thorough understanding of
> > > > > aggregation)?
>
> > > It looks like a bug in django at first glance. Out of curiosity what
> > > version of Django is it, since it looks a tiny bit like an old bug with
> > > queryset chaining, but I think that was fixed even before the first beta.
> > >>> django.get_version()
>
> > u'1.1 beta 1 SVN-10916'
>
> Hmm, after updating to u'1.1 beta 1 SVN-10921' I'm now getting a
> psycopg2.ProgrammingError: ORDER BY "last_updated" is ambiguous.
>
> I've put the SQL it generates (I've only sanitized the two table
> names) up athttp://dpaste.com/51213/
And of course, therein lies my problem, I've gone and tried to
annotate each record with a 'last_updated' calculation, and the model
already has an actual 'last_updated' field. The error only shows up
when django tries to tell the SQL engine to order_by something that's
been defined twice in the query.
I'll raise a ticket on the tracker about possibly raising an exception
instead of allowing users (stupid ones like me) to clobber their own
namespaces.
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