#12560: Unique validation should not check for null atuo-assigned PK
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Reporter: kmtracey | Owner: nobody
Status: new | Milestone: 1.2
Component: Uncategorized | Version: SVN
Keywords: | Stage: Unreviewed
Has_patch: 0 |
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Initially noted here:
http://groups.google.com/group/django-
developers/browse_thread/thread/b45c4d599ea93b74#
The model validation unique check code is issuing an unnecessary query
when adding new instances of models with auto-assigned PKs:
{{{
Python 2.5.2 (r252:60911, Oct 5 2008, 19:24:49)
[GCC 4.3.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> import django
>>> django.get_version()
u'1.2 alpha 1 SVN-12120'
>>> from ttt.models import Tag
>>> from django import forms
>>> class TagForm(forms.ModelForm):
... class Meta:
... model = Tag
...
>>> tf1 = TagForm({'name': 'T1'})
>>> tf1.is_valid()
True
>>> from django.db import connection
>>> connection.queries
[{'time': '0.002', 'sql': u'SELECT (1) AS `a`, `ttt_tag`.`id`,
`ttt_tag`.`name` FROM `ttt_tag` WHERE `ttt_tag`.`id` IS NULL LIMIT 1'}]
>>>
}}}
Besides being unnecessary, that's a query that will potentially return an
unexpected result on MySQL, see: http://groups.google.com/group/django-
developers/browse_thread/thread/d4180b8addf5e970/
This is similar to #12132, only for adding new instances instead of
changing existing ones.
--
Ticket URL: <http://code.djangoproject.com/ticket/12560>
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