Hi,
I have been testing the 1.2 beta1 and think I found a bug, but since
the query I'm using is a bit complicated I wanted to run it through
the list first.
The model I'm using:
from django.db import models
from django.contrib.auth.models import User
class Foo(models.Model):
subject = models.CharField(max_length=120)
sender = models.ForeignKey(User, related_name='sent_foo')
recipient = models.ForeignKey(User, related_name='received_foo')
conversation = models.ForeignKey('self', null=True, blank=True)
It's a basic messaging system, in which you can group messages by
conversations : when saving a new Foo object, you can give it an
existing Foo id to form a conversation. I want to display the "inbox"
for a user, which should be a list with the last message from each
conversation. The following code works in 1.1:
from django.db.models import Max
def conversations(self, user):
tmp =
Foo.objects.values('conversation').annotate(Max('id')).values_list('id__max',
flat=True).order_by( 'conversation')
return Foo.objects.filter(id__in=tmp.filter(recipient=user))
However, in 1.2 beta 1, with postgresql_psycopg2, it fails with:
DatabaseError: aggregates not allowed in WHERE clause
LINE 1: ...d" FROM "mat_foo" WHERE "mat_foo"."id" IN (SELECT MAX("mat_f...
The generated SQL queries are a bit different. Here is django 1.2:
SELECT "mat_foo"."id", "mat_foo"."subject", "mat_foo"."sender_id",
"mat_foo"."recipient_id", "mat_foo"."conversation_id" FROM "mat_foo"
WHERE "mat_foo"."id" IN (SELECT MAX("mat_foo"."id") AS "id__max" FROM
"mat_foo" U0 WHERE U0."recipient_id" = 1 GROUP BY
U0."conversation_id")
And here is django 1.1:
SELECT "mat_foo"."id", "mat_foo"."subject", "mat_foo"."sender_id",
"mat_foo"."recipient_id", "mat_foo"."conversation_id" FROM "mat_foo"
WHERE "mat_foo"."id" IN (SELECT MAX(U0."id") AS "id__max" FROM
"mat_foo" U0 WHERE U0."recipient_id" = 1 GROUP BY
U0."conversation_id")
The only difference is in the MAX() clause. Anyone can enlighten me
about what's happening ? Is that a (known?) django 1.2 bug or am I
pushing the ORM a little too far? It looks like sqlite doesn't
complain with the same code, but I didn't test if the results were
right.
Thanks
--
You received this message because you are subscribed to the Google Groups
"Django users" group.
To post to this group, send email to django-us...@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.
