Hi greenie, you just need to override the save method from your model Restaurant. Before saving each instance, you check if the restaurant already has 3 Cuisine's objects associated. If yes, you don't save the instance and raise an error for exemple, if no, just call the standard method of the super class Model. You will find more infos in the django documentation: http://docs.djangoproject.com/en/dev/topics/db/models/#overriding-predefined-model-methods
On 11 mar, 18:06, greenie2600 <greenie2...@gmail.com> wrote: > Hi all - > > I have two models with a many-to-many relationship: Restaurant and > Cuisine. The Cuisine table contains, e.g., "Italian", "Mexican", > "Chinese", etc. Each Restaurant record can be associated with one or > more Cuisines. > > Here's the thing: I'd like to limit this to three Cuisines per > Restaurant. So when editing the record for "Bob's Pan-Asian Buffet", > the user would be able to check "Japanese", "Chinese", and "Korean", > but wouldn't be able to check a fourth box. > > My question: can this be enforced within the model, or is this > something I'd have to build into my interface layer? > > Here's my models.py. > > from django.db import models > from django.contrib.auth.models import User > > class Restaurant( models.Model ): > > user = models.ForeignKey( User ) > name = models.CharField( max_length = 128 ) > slug = models.CharField( max_length = 24, unique = True ) > cuisines = models.ManyToManyField( 'Cuisine' ) > > def __unicode__(self): > return self.name > > class Cuisine( models.Model ): > > name = models.CharField( max_length = 32 ) > > def __unicode__(self): > return self.name > > class Meta: > ordering = ['name'] -- 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.
