Re: validation error in Django Admin
Thanks for the follow up! On Wednesday, December 12, 2012 4:21:59 PM UTC-8, Mike Dewhirst wrote: > > I'm getting an unexpected validation error in Admin which baffles me. > Any hints appreciated ... here is the traceback > > http://dpaste.com/844972/ > > At the bottom of the traceback where the error is raised, the local vars > are ... > > self > value u'33' > key 'pk' > > When I save the item, it auto-generates many-to-many connections to a > few standard images in the database via a through table. However there > is a rule which says "if ever these two images are connected to an item, > only keep this one and drop that one." > > I use a post-save signal to "drop that one" using ... > >Item_Pictogram.objects.filter(item=instance, pictogram=pic, > via='auto').delete() > > The local var value above being u'33' happens to be the exact pk of the > Item_Pictogram record I want to delete - I checked in Postgres. > > The pk should be an integer but I suppose that's nothing. > > Thanks for any help > > Mike > -- You received this message because you are subscribed to the Google Groups "Django users" group. To view this discussion on the web visit https://groups.google.com/d/msg/django-users/-/RWA0t5qZKCYJ. To post to this group, send email to django-users@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.
[Solved] validation error in Django Admin
Thanks Chris It turned out I hadn't read the docs properly. Prior to posting the problem I had tried ... instance.item_pictogram_set.remove(pic) ... to be told the relatedmanager object didn't have a remove attribute when (I thought) it should. So I adjusted the database to make both fk fields nullable and deliberately made them None to get the code working. But I should have stuck with nullable foreign keys and the above instance.item_pictogram_set.remove(pic) because that was all that is required. I hadn't read beyond the example code in the docs [1] for the remove method where it says ... "In order to prevent database inconsistency, this method only exists on ForeignKey objects where null=True. If the related field can't be set to None (NULL), then an object can't be removed from a relation without being added to another. In the above example, removing e from b.entry_set() is equivalent to doing e.blog = None, and because the blog ForeignKey doesn't have null=True, this is invalid." [1] https://docs.djangoproject.com/en/dev/ref/models/relations/#django.db.models.fields.related.RelatedManager.remove Mike On 13/12/2012 11:30pm, Chris Cogdon wrote: I'm going to take a guess that when you "drop one" of them, deleting it, there's still a query going on that might want to refer to the other one, and the to_python fails because that reference doesn't exist anymore. You might have better luck if you're using a OneToOne or ForeignKey (onetomany), which will let django manage that relationship for you. On Wednesday, December 12, 2012 4:21:59 PM UTC-8, Mike Dewhirst wrote: I'm getting an unexpected validation error in Admin which baffles me. Any hints appreciated ... here is the traceback http://dpaste.com/844972/ At the bottom of the traceback where the error is raised, the local vars are ... self value u'33' key 'pk' When I save the item, it auto-generates many-to-many connections to a few standard images in the database via a through table. However there is a rule which says "if ever these two images are connected to an item, only keep this one and drop that one." I use a post-save signal to "drop that one" using ... Item_Pictogram.objects.filter(item=instance, pictogram=pic, via='auto').delete() The local var value above being u'33' happens to be the exact pk of the Item_Pictogram record I want to delete - I checked in Postgres. The pk should be an integer but I suppose that's nothing. Thanks for any help Mike -- You received this message because you are subscribed to the Google Groups "Django users" group. To view this discussion on the web visit https://groups.google.com/d/msg/django-users/-/TjN8sz1YkQwJ. To post to this group, send email to django-users@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. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@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.
Re: validation error in Django Admin
I'm going to take a guess that when you "drop one" of them, deleting it, there's still a query going on that might want to refer to the other one, and the to_python fails because that reference doesn't exist anymore. You might have better luck if you're using a OneToOne or ForeignKey (onetomany), which will let django manage that relationship for you. On Wednesday, December 12, 2012 4:21:59 PM UTC-8, Mike Dewhirst wrote: > > I'm getting an unexpected validation error in Admin which baffles me. > Any hints appreciated ... here is the traceback > > http://dpaste.com/844972/ > > At the bottom of the traceback where the error is raised, the local vars > are ... > > self > value u'33' > key 'pk' > > When I save the item, it auto-generates many-to-many connections to a > few standard images in the database via a through table. However there > is a rule which says "if ever these two images are connected to an item, > only keep this one and drop that one." > > I use a post-save signal to "drop that one" using ... > >Item_Pictogram.objects.filter(item=instance, pictogram=pic, > via='auto').delete() > > The local var value above being u'33' happens to be the exact pk of the > Item_Pictogram record I want to delete - I checked in Postgres. > > The pk should be an integer but I suppose that's nothing. > > Thanks for any help > > Mike > -- You received this message because you are subscribed to the Google Groups "Django users" group. To view this discussion on the web visit https://groups.google.com/d/msg/django-users/-/TjN8sz1YkQwJ. To post to this group, send email to django-users@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.
validation error in Django Admin
I'm getting an unexpected validation error in Admin which baffles me. Any hints appreciated ... here is the traceback http://dpaste.com/844972/ At the bottom of the traceback where the error is raised, the local vars are ... self value u'33' key 'pk' When I save the item, it auto-generates many-to-many connections to a few standard images in the database via a through table. However there is a rule which says "if ever these two images are connected to an item, only keep this one and drop that one." I use a post-save signal to "drop that one" using ... Item_Pictogram.objects.filter(item=instance, pictogram=pic, via='auto').delete() The local var value above being u'33' happens to be the exact pk of the Item_Pictogram record I want to delete - I checked in Postgres. The pk should be an integer but I suppose that's nothing. Thanks for any help Mike -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@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.
