mirrors/django
1
0
Fork 0
mirror of https://github.com/django/django.git synced 2025-10-24 14:16:09 +00:00
Code Issues 32 Releases Wiki Activity

Allowed custom querysets when prefetching single valued relations

Browse Source 
The original patch for custom prefetches didn't allow usage of custom
queryset for single valued relations (along ForeignKey or OneToOneKey).
Allowing these enables calling performance oriented queryset methods like
select_related or defer/only.

Thanks @akaariai and @timgraham for the reviews. Refs #17001.
This commit is contained in:
Loic Bistuer
2014-01-17 01:24:39 +07:00
committed by Anssi Kääriäinen
parent c8d61fa109
commit 7bbb6958dc
5 changed files with 112 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

73
tests/prefetch_related/tests.py
View File

@@ -1,5 +1,6 @@
from __future__ import unicode_literals
from django.core.exceptions import ObjectDoesNotExist
from django.contrib.contenttypes.models import ContentType
from django.db import connection
from django.db.models import Prefetch
@@ -228,17 +229,22 @@ class CustomPrefetchTests(TestCase):
for part in path:
if not part:
continue
rel_objs.extend(cls.traverse_qs(getattr(obj, part[0]), [part[1:]]))
try:
related = getattr(obj, part[0])
except ObjectDoesNotExist:
continue
if related is not None:
rel_objs.extend(cls.traverse_qs(related, [part[1:]]))
ret_val.append((obj, rel_objs))
return ret_val
def setUp(self):
self.person1 = Person.objects.create(name="Joe")
self.person2 = Person.objects.create(name="Mary")
self.house1 = House.objects.create(address="123 Main St", owner=self.person1)
self.house2 = House.objects.create(address="45 Side St", owner=self.person1)
self.house3 = House.objects.create(address="6 Downing St", owner=self.person2)
self.house4 = House.objects.create(address="7 Regents St", owner=self.person2)
self.house1 = House.objects.create(name='House 1', address="123 Main St", owner=self.person1)
self.house2 = House.objects.create(name='House 2', address="45 Side St", owner=self.person1)
self.house3 = House.objects.create(name='House 3', address="6 Downing St", owner=self.person2)
self.house4 = House.objects.create(name='house 4', address="7 Regents St", owner=self.person2)
self.room1_1 = Room.objects.create(name="Dining room", house=self.house1)
self.room1_2 = Room.objects.create(name="Lounge", house=self.house1)
self.room1_3 = Room.objects.create(name="Kitchen", house=self.house1)
@@ -253,6 +259,14 @@ class CustomPrefetchTests(TestCase):
self.room4_3 = Room.objects.create(name="Kitchen", house=self.house4)
self.person1.houses.add(self.house1, self.house2)
self.person2.houses.add(self.house3, self.house4)
self.house1.main_room = self.room1_1
self.house1.save()
self.house2.main_room = self.room2_1
self.house2.save()
self.house3.main_room = self.room3_1
self.house3.save()
self.house4.main_room = self.room4_1
self.house4.save()
def test_traverse_qs(self):
qs = Person.objects.prefetch_related('houses')
@@ -262,16 +276,17 @@ class CustomPrefetchTests(TestCase):
self.assertEqual(related_objs_normal, (related_objs_from_traverse,))
def test_ambiguous(self):
# Ambiguous.
# Ambiguous: Lookup was already seen with a different queryset.
with self.assertRaises(ValueError):
self.traverse_qs(
Person.objects.prefetch_related('houses__rooms', Prefetch('houses', queryset=House.objects.all())),
[['houses', 'rooms']]
)
# Ambiguous: Lookup houses_lst doesn't yet exist when performing houses_lst__rooms.
with self.assertRaises(AttributeError):
self.traverse_qs(
Person.objects.prefetch_related('houses_list__rooms', Prefetch('houses', queryset=House.objects.all(), to_attr='houses_lst')),
Person.objects.prefetch_related('houses_lst__rooms', Prefetch('houses', queryset=House.objects.all(), to_attr='houses_lst')),
[['houses', 'rooms']]
)
@@ -491,6 +506,50 @@ class CustomPrefetchTests(TestCase):
self.assertEqual(lst2[0].houses_lst[0].rooms_lst[1], self.room1_2)
self.assertEqual(len(lst2[1].houses_lst), 0)
# Test ReverseSingleRelatedObjectDescriptor.
houses = House.objects.select_related('owner')
with self.assertNumQueries(6):
rooms = Room.objects.all().prefetch_related('house')
lst1 = self.traverse_qs(rooms, [['house', 'owner']])
with self.assertNumQueries(2):
rooms = Room.objects.all().prefetch_related(Prefetch('house', queryset=houses.all()))
lst2 = self.traverse_qs(rooms, [['house', 'owner']])
self.assertEqual(lst1, lst2)
with self.assertNumQueries(2):
houses = House.objects.select_related('owner')
rooms = Room.objects.all().prefetch_related(Prefetch('house', queryset=houses.all(), to_attr='house_attr'))
lst2 = self.traverse_qs(rooms, [['house_attr', 'owner']])
self.assertEqual(lst1, lst2)
room = Room.objects.all().prefetch_related(Prefetch('house', queryset=houses.filter(address='DoesNotExist'))).first()
with self.assertRaises(ObjectDoesNotExist):
getattr(room, 'house')
room = Room.objects.all().prefetch_related(Prefetch('house', queryset=houses.filter(address='DoesNotExist'), to_attr='house_attr')).first()
self.assertIsNone(room.house_attr)
rooms = Room.objects.all().prefetch_related(Prefetch('house', queryset=House.objects.only('name')))
with self.assertNumQueries(2):
getattr(rooms.first().house, 'name')
with self.assertNumQueries(3):
getattr(rooms.first().house, 'address')
# Test SingleRelatedObjectDescriptor.
houses = House.objects.select_related('owner')
with self.assertNumQueries(6):
rooms = Room.objects.all().prefetch_related('main_room_of')
lst1 = self.traverse_qs(rooms, [['main_room_of', 'owner']])
with self.assertNumQueries(2):
rooms = Room.objects.all().prefetch_related(Prefetch('main_room_of', queryset=houses.all()))
lst2 = self.traverse_qs(rooms, [['main_room_of', 'owner']])
self.assertEqual(lst1, lst2)
with self.assertNumQueries(2):
rooms = list(Room.objects.all().prefetch_related(Prefetch('main_room_of', queryset=houses.all(), to_attr='main_room_of_attr')))
lst2 = self.traverse_qs(rooms, [['main_room_of_attr', 'owner']])
self.assertEqual(lst1, lst2)
room = Room.objects.filter(main_room_of__isnull=False).prefetch_related(Prefetch('main_room_of', queryset=houses.filter(address='DoesNotExist'))).first()
with self.assertRaises(ObjectDoesNotExist):
getattr(room, 'main_room_of')
room = Room.objects.filter(main_room_of__isnull=False).prefetch_related(Prefetch('main_room_of', queryset=houses.filter(address='DoesNotExist'), to_attr='main_room_of_attr')).first()
self.assertIsNone(room.main_room_of_attr)
class DefaultManagerTests(TestCase):