edit: you don't need to raise an error if the restaurant already has 3 Cuisine's objects associated, you just need to return a string with the explanation of the error.
On 11 mar, 20:11, gontran <geoffroydecorb...@gmail.com> wrote: > 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-pre... > > 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.
