Opened 7 years ago

Closed 3 years ago

#12501 closed Bug (fixed)

Inconsistent behaviour in querying and creating objects

Reported by: DmitryRisenberg Owned by: nobody
Component: Database layer (models, ORM) Version: 1.1
Severity: Normal Keywords:
Cc: commando@… Triage Stage: Accepted
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description

I have a strange behaviour for the following models:

from django.db import models

class Channel(models.Model):
    def createSubscription(self):
        subscription = Subscription.objects.create(channel = self)
        print Subscription.objects.filter(channel = self)
        return subscription

class FeedChannel(Channel):
    link = models.CharField(max_length = 200, primary_key = True)

class Subscription(models.Model):
    channel = models.ForeignKey(Channel)

This is what I get when I run ./manage.py shell with a newly created DB:

>>> from smth import models
>>> c = models.FeedChannel.objects.create()
>>> s = c.createSubscription()
[]
>>> print s.channel.id, c.channel_ptr.id
1 1
>>>
>>>

The filter query in createSubscription does not include the created object. I either expect the filter query to select the newly created Subscription object, because its channel field points to the correct Channel instance, or the create query to fail when it encounters an object of derived type instead of base.

Without the primary_key constraint on link field everything works just as expected.

I am using Django 1.1 and Python 2.5.

Change History (5)

comment:1 Changed 7 years ago by Russell Keith-Magee

Needs documentation: unset
Needs tests: unset
Patch needs improvement: unset
Triage Stage: UnreviewedAccepted

By putting the primary_key flag on the link, channel=self is no longer able to roll out as channel=self.pk. Some additional checks will be required internally to make sure the right parent link/value is used.

comment:2 Changed 5 years ago by Matt McClanahan

Severity: Normal
Type: Bug

comment:3 Changed 5 years ago by Aymeric Augustin

UI/UX: unset

Change UI/UX from NULL to False.

comment:4 Changed 5 years ago by Aymeric Augustin

Easy pickings: unset

Change Easy pickings from NULL to False.

comment:5 Changed 3 years ago by Anssi Kääriäinen

Resolution: fixed
Status: newclosed

This seems to be fixed in master. I am somewhat confident that this one has been tested already so I won't add more tests for this).

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