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	* Model init no longer performs a database query to refetch the related objects it is passed. * Model init now caches unsaved related objects correctly, too. (Previously, accessing the field would raise `DoesNotExist` error for `null=False` fields.) * Added tests for assigning `None` to `null=True` `ForeignKey` fields (refs #6886). git-svn-id: http://code.djangoproject.com/svn/django/trunk@8185 bcc190cf-cafb-0310-a4f2-bffc1f526a37
		
			
				
	
	
		
			123 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			123 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| from django.db import models
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| 
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| class Place(models.Model):
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|     name = models.CharField(max_length=50)
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|     address = models.CharField(max_length=80)
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| 
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|     def __unicode__(self):
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|         return u"%s the place" % self.name
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| 
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| class Restaurant(models.Model):
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|     place = models.OneToOneField(Place)
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|     serves_hot_dogs = models.BooleanField()
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|     serves_pizza = models.BooleanField()
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| 
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|     def __unicode__(self):
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|         return u"%s the restaurant" % self.place.name
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| 
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| class Bar(models.Model):
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|     place = models.OneToOneField(Place)
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|     serves_cocktails = models.BooleanField()
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| 
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|     def __unicode__(self):
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|         return u"%s the bar" % self.place.name
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| 
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| class UndergroundBar(models.Model):
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|     place = models.OneToOneField(Place, null=True)
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|     serves_cocktails = models.BooleanField()
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| 
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| class Favorites(models.Model):
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|     name = models.CharField(max_length = 50)
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|     restaurants = models.ManyToManyField(Restaurant)
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| 
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|     def __unicode__(self):
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|         return u"Favorites for %s" % self.name
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| 
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| __test__ = {'API_TESTS':"""
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| # Regression test for #1064 and #1506: Check that we create models via the m2m
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| # relation if the remote model has a OneToOneField.
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| >>> p1 = Place(name='Demon Dogs', address='944 W. Fullerton')
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| >>> p1.save()
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| >>> r = Restaurant(place=p1, serves_hot_dogs=True, serves_pizza=False)
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| >>> r.save()
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| >>> f = Favorites(name = 'Fred')
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| >>> f.save()
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| >>> f.restaurants = [r]
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| >>> f.restaurants.all()
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| [<Restaurant: Demon Dogs the restaurant>]
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| 
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| # Regression test for #7173: Check that the name of the cache for the
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| # reverse object is correct.
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| >>> b = Bar(place=p1, serves_cocktails=False)
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| >>> b.save()
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| >>> p1.restaurant
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| <Restaurant: Demon Dogs the restaurant>
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| >>> p1.bar
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| <Bar: Demon Dogs the bar>
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| 
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| #
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| # Regression test for #6886 (the related-object cache)
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| #
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| 
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| # Look up the objects again so that we get "fresh" objects
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| >>> p = Place.objects.get(name="Demon Dogs")
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| >>> r = p.restaurant
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| 
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| # Accessing the related object again returns the exactly same object
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| >>> p.restaurant is r
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| True
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| 
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| # But if we kill the cache, we get a new object
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| >>> del p._restaurant_cache
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| >>> p.restaurant is r
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| False
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| 
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| # Reassigning the Restaurant object results in an immediate cache update
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| # We can't use a new Restaurant because that'll violate one-to-one, but
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| # with a new *instance* the is test below will fail if #6886 regresses.
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| >>> r2 = Restaurant.objects.get(pk=r.pk)
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| >>> p.restaurant = r2
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| >>> p.restaurant is r2
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| True
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| 
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| # Assigning None succeeds if field is null=True.
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| >>> ug_bar = UndergroundBar.objects.create(place=p, serves_cocktails=False)
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| >>> ug_bar.place = None
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| >>> ug_bar.place is None
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| True
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| 
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| # Assigning None fails: Place.restaurant is null=False
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| >>> p.restaurant = None
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| Traceback (most recent call last):
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|     ...
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| ValueError: Cannot assign None: "Place.restaurant" does not allow null values.
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| 
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| # You also can't assign an object of the wrong type here
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| >>> p.restaurant = p
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| Traceback (most recent call last):
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|     ...
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| ValueError: Cannot assign "<Place: Demon Dogs the place>": "Place.restaurant" must be a "Restaurant" instance.
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| 
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| # Creation using keyword argument should cache the related object.
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| >>> p = Place.objects.get(name="Demon Dogs")
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| >>> r = Restaurant(place=p)
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| >>> r.place is p
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| True
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| 
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| # Creation using keyword argument and unsaved related instance (#8070).
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| >>> p = Place()
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| >>> r = Restaurant(place=p)
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| >>> r.place is p
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| True
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| 
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| # Creation using attname keyword argument and an id will cause the related
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| # object to be fetched.
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| >>> p = Place.objects.get(name="Demon Dogs")
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| >>> r = Restaurant(place_id=p.id)
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| >>> r.place is p
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| False
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| >>> r.place == p
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| True
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| 
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| """}
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