On Tue, Sep 16, 2008 at 12:49 PM, Steven <[EMAIL PROTECTED]> wrote: > > I just got started with Django (I'm using v1.0).. and have been trying > (unsuccessfully) to add this line to my first model "author = > models.ForeignKey(User)"... (see my models.py below). Everytime I do > so and sync I get the following message: > > ^[[31;1mError: One or more models did not validate: > ^[[31;1mauth.message: Accessor for field 'user' clashes with related > field 'User.message_set'. Add \ > a related_name argument to the definition for 'user'. > ^[[0m^[[31;1mmusables.message: Accessor for field 'author' clashes > with related field 'User.message\ > _set'. Add a related_name argument to the definition for 'author'. > ^[[0m > > The odd thing is I decided to copy my model (see below it is called > MessageV2) and then it worked fine? Is there something "magical" > about the first model you define in a file? Is Django storing some > extra state somewhere.. btw.. i've been "DROP TABLE"ing all my tables > before manage.py syncdb ? > > Steven > > > ===== models.py ====== > > from django.db import models > from django.contrib.auth.models import User > > # Create your models here. > > class Message(models.Model): > sent_date = models.DateTimeField() > subject = models.CharField(max_length = 100) > body = models.TextField() > slug = models.SlugField(max_length = 100) > # author = models.ForeignKey(User) # uncommenting this causes the > problem > def __unicode__(self): > return self.subject > > class MessageV2(models.Model): > sent_date = models.DateTimeField() > subject = models.CharField(max_length = 100) > body = models.TextField() > slug = models.SlugField(max_length = 100) > author = models.ForeignKey(User) # this is where things are > confusing > > def __unicode__(self): > return self.subject > > When you define a ForeignKey, the target model acquires an accessor to retrieve the set of models with ForeignKey values that specify it. The name of that accessor is the name of the model where the ForeignKey is defined (lower-cased), plus '_set'. This is probabably explained with better words in the documentation:
http://docs.djangoproject.com/en/dev/topics/db/queries/#following-relationships-backward Your problem is you are defining a model Message with a ForeignKey to User when the django.contrib.auth application already has a different model Message with ForeignKey to User, see: http://docs.djangoproject.com/en/dev/topics/auth/#messages Thus validation determines that there are going to be two different 'message_set' accessors on User, and validation fails. You can either use the related_name argument on your ForeignKey to change the name for the accessor, or you can change the name of your model to something other than Message (which is why your 2nd model works, it's not because it is the 2nd model but rather because its name does not duplicate another model's name that has a ForeignKey to User). Karen --~--~---------~--~----~------------~-------~--~----~ 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 [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
