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other database backends, but the exception classes should still be the same. This commit changes the way the tests check for specific database errors to be more portable between implementations. It's possible these tests will still fail if, e.g., Oracle doesn't raise IntegrityError (but raises DatabaseError) when we except it to, but we can cross that bridge if and when it appears. git-svn-id: http://code.djangoproject.com/svn/django/trunk@8450 bcc190cf-cafb-0310-a4f2-bffc1f526a37
193 lines
6.1 KiB
Python
193 lines
6.1 KiB
Python
"""
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10. One-to-one relationships
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To define a one-to-one relationship, use ``OneToOneField()``.
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In this example, a ``Place`` optionally can be a ``Restaurant``.
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"""
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from django.db import models, transaction, IntegrityError
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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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def __unicode__(self):
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return u"%s the place" % self.name
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class Restaurant(models.Model):
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place = models.OneToOneField(Place, primary_key=True)
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serves_hot_dogs = models.BooleanField()
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serves_pizza = models.BooleanField()
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def __unicode__(self):
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return u"%s the restaurant" % self.place.name
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class Waiter(models.Model):
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restaurant = models.ForeignKey(Restaurant)
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name = models.CharField(max_length=50)
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def __unicode__(self):
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return u"%s the waiter at %s" % (self.name, self.restaurant)
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class ManualPrimaryKey(models.Model):
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primary_key = models.CharField(max_length=10, primary_key=True)
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name = models.CharField(max_length = 50)
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class RelatedModel(models.Model):
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link = models.OneToOneField(ManualPrimaryKey)
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name = models.CharField(max_length = 50)
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class MultiModel(models.Model):
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link1 = models.OneToOneField(Place)
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link2 = models.OneToOneField(ManualPrimaryKey)
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name = models.CharField(max_length=50)
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def __unicode__(self):
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return u"Multimodel %s" % self.name
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__test__ = {'API_TESTS':"""
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# Create a couple of Places.
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>>> p1 = Place(name='Demon Dogs', address='944 W. Fullerton')
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>>> p1.save()
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>>> p2 = Place(name='Ace Hardware', address='1013 N. Ashland')
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>>> p2.save()
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# Create a Restaurant. Pass the ID of the "parent" object as this object's ID.
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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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# A Restaurant can access its place.
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>>> r.place
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<Place: Demon Dogs the place>
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# A Place can access its restaurant, if available.
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>>> p1.restaurant
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<Restaurant: Demon Dogs the restaurant>
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# p2 doesn't have an associated restaurant.
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>>> p2.restaurant
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Traceback (most recent call last):
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...
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DoesNotExist: Restaurant matching query does not exist.
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# Set the place using assignment notation. Because place is the primary key on
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# Restaurant, the save will create a new restaurant
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>>> r.place = p2
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>>> r.save()
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>>> p2.restaurant
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<Restaurant: Ace Hardware the restaurant>
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>>> r.place
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<Place: Ace Hardware the place>
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# Set the place back again, using assignment in the reverse direction.
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>>> p1.restaurant = r
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>>> p1.restaurant
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<Restaurant: Demon Dogs the restaurant>
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>>> r = Restaurant.objects.get(pk=1)
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>>> r.place
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<Place: Demon Dogs the place>
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# Restaurant.objects.all() just returns the Restaurants, not the Places.
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# Note that there are two restaurants - Ace Hardware the Restaurant was created
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# in the call to r.place = p2.
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>>> Restaurant.objects.all()
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[<Restaurant: Demon Dogs the restaurant>, <Restaurant: Ace Hardware the restaurant>]
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# Place.objects.all() returns all Places, regardless of whether they have
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# Restaurants.
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>>> Place.objects.order_by('name')
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[<Place: Ace Hardware the place>, <Place: Demon Dogs the place>]
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>>> Restaurant.objects.get(place__id__exact=1)
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<Restaurant: Demon Dogs the restaurant>
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>>> Restaurant.objects.get(pk=1)
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<Restaurant: Demon Dogs the restaurant>
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>>> Restaurant.objects.get(place__exact=1)
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<Restaurant: Demon Dogs the restaurant>
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>>> Restaurant.objects.get(place__exact=p1)
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<Restaurant: Demon Dogs the restaurant>
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>>> Restaurant.objects.get(place=1)
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<Restaurant: Demon Dogs the restaurant>
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>>> Restaurant.objects.get(place=p1)
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<Restaurant: Demon Dogs the restaurant>
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>>> Restaurant.objects.get(place__pk=1)
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<Restaurant: Demon Dogs the restaurant>
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>>> Restaurant.objects.get(place__name__startswith="Demon")
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<Restaurant: Demon Dogs the restaurant>
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>>> Place.objects.get(id__exact=1)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(pk=1)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(restaurant__place__exact=1)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(restaurant__place__exact=p1)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(restaurant__pk=1)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(restaurant=1)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(restaurant=r)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(restaurant__exact=1)
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<Place: Demon Dogs the place>
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>>> Place.objects.get(restaurant__exact=r)
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<Place: Demon Dogs the place>
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# Add a Waiter to the Restaurant.
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>>> w = r.waiter_set.create(name='Joe')
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>>> w.save()
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>>> w
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<Waiter: Joe the waiter at Demon Dogs the restaurant>
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# Query the waiters
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>>> Waiter.objects.filter(restaurant__place__pk=1)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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>>> Waiter.objects.filter(restaurant__place__exact=1)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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>>> Waiter.objects.filter(restaurant__place__exact=p1)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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>>> Waiter.objects.filter(restaurant__pk=1)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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>>> Waiter.objects.filter(id__exact=1)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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>>> Waiter.objects.filter(pk=1)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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>>> Waiter.objects.filter(restaurant=1)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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>>> Waiter.objects.filter(restaurant=r)
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[<Waiter: Joe the waiter at Demon Dogs the restaurant>]
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# Delete the restaurant; the waiter should also be removed
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>>> r = Restaurant.objects.get(pk=1)
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>>> r.delete()
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# One-to-one fields still work if you create your own primary key
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>>> o1 = ManualPrimaryKey(primary_key="abc123", name="primary")
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>>> o1.save()
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>>> o2 = RelatedModel(link=o1, name="secondary")
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>>> o2.save()
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# You can have multiple one-to-one fields on a model, too.
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>>> x1 = MultiModel(link1=p1, link2=o1, name="x1")
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>>> x1.save()
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>>> o1.multimodel
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<MultiModel: Multimodel x1>
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# This will fail because each one-to-one field must be unique (and link2=o1 was
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# used for x1, above).
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>>> sid = transaction.savepoint()
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>>> try:
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... MultiModel(link1=p2, link2=o1, name="x1").save()
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... except Exception, e:
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... if isinstance(e, IntegrityError):
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... print "Pass"
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... else:
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... print "Fail with %s" % type(e)
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Pass
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>>> transaction.savepoint_rollback(sid)
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"""}
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