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Fixed #15250 -- Avoided extra query on some multi-table inheritance queries.

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Thanks marekw2143 for the initial patch and carljm for support.
This commit is contained in:
Paulo 2016-06-02 17:44:47 -07:00 • committed by Tim Graham
parent 9899347641
commit 38575b007a
4 changed files with 74 additions and 15 deletions
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32
tests/model_inheritance_regress/tests.py
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@ -496,3 +496,35 @@ class ModelInheritanceTest(TestCase):
r.supplier_set.all(),
[s], lambda x: x,
)
def test_queries_on_parent_access(self):
italian_restaurant = ItalianRestaurant.objects.create(
name="Guido's House of Pasta",
address='944 W. Fullerton',
serves_hot_dogs=True,
serves_pizza=False,
serves_gnocchi=True,
)
# No queries are made when accessing the parent objects.
italian_restaurant = ItalianRestaurant.objects.get(pk=italian_restaurant.pk)
with self.assertNumQueries(0):
restaurant = italian_restaurant.restaurant_ptr
self.assertEqual(restaurant.place_ptr.restaurant, restaurant)
self.assertEqual(restaurant.italianrestaurant, italian_restaurant)
# One query is made when accessing the parent objects when the instance
# is deferred.
italian_restaurant = ItalianRestaurant.objects.only('serves_gnocchi').get(pk=italian_restaurant.pk)
with self.assertNumQueries(1):
restaurant = italian_restaurant.restaurant_ptr
self.assertEqual(restaurant.place_ptr.restaurant, restaurant)
self.assertEqual(restaurant.italianrestaurant, italian_restaurant)
# No queries are made when accessing the parent objects when the
# instance has deferred a field not present in the parent table.
italian_restaurant = ItalianRestaurant.objects.defer('serves_gnocchi').get(pk=italian_restaurant.pk)
with self.assertNumQueries(0):
restaurant = italian_restaurant.restaurant_ptr
self.assertEqual(restaurant.place_ptr.restaurant, restaurant)
self.assertEqual(restaurant.italianrestaurant, italian_restaurant)