from django.db import models class Place(models.Model): name = models.CharField(max_length=50) address = models.CharField(max_length=80) def __unicode__(self): return u"%s the place" % self.name class Restaurant(models.Model): place = models.OneToOneField(Place) serves_hot_dogs = models.BooleanField() serves_pizza = models.BooleanField() def __unicode__(self): return u"%s the restaurant" % self.place.name class Bar(models.Model): place = models.OneToOneField(Place) serves_cocktails = models.BooleanField() def __unicode__(self): return u"%s the bar" % self.place.name class Favorites(models.Model): name = models.CharField(max_length = 50) restaurants = models.ManyToManyField(Restaurant) def __unicode__(self): return u"Favorites for %s" % self.name __test__ = {'API_TESTS':""" # Regression test for #1064 and #1506: Check that we create models via the m2m # relation if the remote model has a OneToOneField. >>> p1 = Place(name='Demon Dogs', address='944 W. Fullerton') >>> p1.save() >>> r = Restaurant(place=p1, serves_hot_dogs=True, serves_pizza=False) >>> r.save() >>> f = Favorites(name = 'Fred') >>> f.save() >>> f.restaurants = [r] >>> f.restaurants.all() [] # Regression test for #7173: Check that the name of the cache for the # reverse object is correct. >>> b = Bar(place=p1, serves_cocktails=False) >>> b.save() >>> p1.restaurant >>> p1.bar # # Regression test for #6886 (the related-object cache) # # Look up the objects again so that we get "fresh" objects >>> p = Place.objects.get(name="Demon Dogs") >>> r = p.restaurant # Accessing the related object again returns the exactly same object >>> p.restaurant is r True # But if we kill the cache, we get a new object >>> del p._restaurant_cache >>> p.restaurant is r False # Reassigning the Restaurant object results in an immediate cache update # We can't use a new Restaurant because that'll violate one-to-one, but # with a new *instance* the is test below will fail if #6886 regresses. >>> r2 = Restaurant.objects.get(pk=r.pk) >>> p.restaurant = r2 >>> p.restaurant is r2 True # Assigning None fails: Place.restaurant is null=False >>> p.restaurant = None Traceback (most recent call last): ... ValueError: Cannot assign None: "Place.restaurant" does not allow null values. # You also can't assign an object of the wrong type here >>> p.restaurant = p Traceback (most recent call last): ... ValueError: Cannot assign "": "Place.restaurant" must be a "Restaurant" instance. """}