mirrors/django
1
0
Fork 0
mirror of https://github.com/django/django.git synced 2025-10-31 09:41:08 +00:00
Code Issues 32 Releases Wiki Activity

Fixed #28586 -- Added model field fetch modes.

Browse Source 
May your database queries be much reduced with minimal effort.

co-authored-by: Andreas Pelme <andreas@pelme.se>
co-authored-by: Simon Charette <charette.s@gmail.com>
co-authored-by: Jacob Walls <jacobtylerwalls@gmail.com>
This commit is contained in:
Adam Johnson
2023-11-29 09:35:34 +00:00
committed by Jacob Walls
parent f6bd90c840
commit e097e8a12f
24 changed files with 682 additions and 73 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
tests/generic_relations/tests.py
View File

@@ -1,7 +1,8 @@
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes.prefetch import GenericPrefetch
from django.core.exceptions import FieldError
from django.core.exceptions import FieldError, FieldFetchBlocked
from django.db.models import Q, prefetch_related_objects
from django.db.models.fetch_modes import FETCH_PEERS, RAISE
from django.test import SimpleTestCase, TestCase, skipUnlessDBFeature
from .models import (
@@ -780,6 +781,46 @@ class GenericRelationsTests(TestCase):
self.platypus.latin_name,
)
def test_fetch_mode_fetch_peers(self):
TaggedItem.objects.bulk_create(
[
TaggedItem(tag="lion", content_object=self.lion),
TaggedItem(tag="platypus", content_object=self.platypus),
TaggedItem(tag="quartz", content_object=self.quartz),
]
)
# Peers fetching should fetch all related peers GFKs at once which is
# one query per content type.
with self.assertNumQueries(1):
quartz_tag, platypus_tag, lion_tag = TaggedItem.objects.fetch_mode(
FETCH_PEERS
).order_by("-pk")[:3]
with self.assertNumQueries(2):
self.assertEqual(lion_tag.content_object, self.lion)
with self.assertNumQueries(0):
self.assertEqual(platypus_tag.content_object, self.platypus)
self.assertEqual(quartz_tag.content_object, self.quartz)
# It should ignore already cached instances though.
with self.assertNumQueries(1):
quartz_tag, platypus_tag, lion_tag = TaggedItem.objects.fetch_mode(
FETCH_PEERS
).order_by("-pk")[:3]
with self.assertNumQueries(2):
self.assertEqual(quartz_tag.content_object, self.quartz)
self.assertEqual(lion_tag.content_object, self.lion)
with self.assertNumQueries(0):
self.assertEqual(platypus_tag.content_object, self.platypus)
self.assertEqual(quartz_tag.content_object, self.quartz)
def test_fetch_mode_raise(self):
TaggedItem.objects.create(tag="lion", content_object=self.lion)
tag = TaggedItem.objects.fetch_mode(RAISE).get(tag="yellow")
msg = "Fetching of TaggedItem.content_object blocked."
with self.assertRaisesMessage(FieldFetchBlocked, msg) as cm:
tag.content_object
self.assertIsNone(cm.exception.__cause__)
self.assertTrue(cm.exception.__suppress_context__)
class ProxyRelatedModelTest(TestCase):
def test_default_behavior(self):