django default foreign key value for users

Question

I've had a read through http://www.b-list.org/weblog/2006/jun/06/django-tips-extending-user-model/ but still am having problems migrating my new db schema with a ForeignKey for a user in a list of products

a simplified version of my code is:

from django.contrib.auth.models import User
# other imports

class Product(models.Model):

 author = models.ForeignKey(User)
 # other product fields..

but when I try to migrate to South, and this may be the problem, as my user database is not handled by South (??forgive my newbieness) i'm getting errors that a default value needs to be set:

_mysql_exceptions.OperationalError: (1067, "Invalid default value for 'author_id'")

Can anyone explain what i'm doing wrong?? Ideally I wouldn't want a default value for the user, or at least null, false or 0 (but that doesn't seem to work)..

many thanks,

adam

Answer 1

If you want it to be possible to have an empty value for author, you need to define the ForeignKey with null=True. You'll probably want blank=True as well, as that controls the validation in Django forms.

author = models.ForeignKey(User, null=True, blank=True)

Answer 2

Ended up taking the easy route and totally resetting the product table, and migrating from scratch which worked. Not sure i've learnt anything (other than how to reset an app)!