mirror of
https://github.com/django/django.git
synced 2025-10-31 09:41:08 +00:00
224 lines
8.4 KiB
Python
224 lines
8.4 KiB
Python
from django.db.models import Prefetch, prefetch_related_objects
|
|
from django.test import TestCase
|
|
|
|
from .models import Author, Book, House, Reader, Room
|
|
|
|
|
|
class PrefetchRelatedObjectsTests(TestCase):
|
|
"""
|
|
Since prefetch_related_objects() is just the inner part of
|
|
prefetch_related(), only do basic tests to ensure its API hasn't changed.
|
|
"""
|
|
|
|
@classmethod
|
|
def setUpTestData(cls):
|
|
cls.book1 = Book.objects.create(title="Poems")
|
|
cls.book2 = Book.objects.create(title="Jane Eyre")
|
|
cls.book3 = Book.objects.create(title="Wuthering Heights")
|
|
cls.book4 = Book.objects.create(title="Sense and Sensibility")
|
|
|
|
cls.author1 = Author.objects.create(name="Charlotte", first_book=cls.book1)
|
|
cls.author2 = Author.objects.create(name="Anne", first_book=cls.book1)
|
|
cls.author3 = Author.objects.create(name="Emily", first_book=cls.book1)
|
|
cls.author4 = Author.objects.create(name="Jane", first_book=cls.book4)
|
|
|
|
cls.book1.authors.add(cls.author1, cls.author2, cls.author3)
|
|
cls.book2.authors.add(cls.author1)
|
|
cls.book3.authors.add(cls.author3)
|
|
cls.book4.authors.add(cls.author4)
|
|
|
|
cls.reader1 = Reader.objects.create(name="Amy")
|
|
cls.reader2 = Reader.objects.create(name="Belinda")
|
|
|
|
cls.reader1.books_read.add(cls.book1, cls.book4)
|
|
cls.reader2.books_read.add(cls.book2, cls.book4)
|
|
|
|
cls.house1 = House.objects.create(name="b1", address="1")
|
|
cls.house2 = House.objects.create(name="b2", address="2")
|
|
|
|
cls.room1 = Room.objects.create(name="a1", house=cls.house1)
|
|
cls.room2 = Room.objects.create(name="a2", house=cls.house2)
|
|
|
|
cls.house1.main_room = cls.room1
|
|
cls.house1.save()
|
|
cls.house2.main_room = cls.room2
|
|
cls.house2.save()
|
|
|
|
def test_unknown(self):
|
|
book1 = Book.objects.get(id=self.book1.id)
|
|
with self.assertRaises(AttributeError):
|
|
prefetch_related_objects([book1], "unknown_attribute")
|
|
|
|
def test_m2m_forward(self):
|
|
book1 = Book.objects.get(id=self.book1.id)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects([book1], "authors")
|
|
|
|
with self.assertNumQueries(0):
|
|
self.assertCountEqual(
|
|
book1.authors.all(), [self.author1, self.author2, self.author3]
|
|
)
|
|
|
|
def test_m2m_reverse(self):
|
|
author1 = Author.objects.get(id=self.author1.id)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects([author1], "books")
|
|
|
|
with self.assertNumQueries(0):
|
|
self.assertCountEqual(author1.books.all(), [self.book1, self.book2])
|
|
|
|
def test_foreignkey_forward(self):
|
|
authors = list(Author.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(authors, "first_book")
|
|
self.assertNotIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
with self.assertNumQueries(0):
|
|
[author.first_book for author in authors]
|
|
|
|
authors = list(Author.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(
|
|
authors,
|
|
Prefetch("first_book", queryset=Book.objects.order_by("-title")),
|
|
)
|
|
self.assertNotIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
def test_foreignkey_reverse(self):
|
|
books = list(Book.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(books, "first_time_authors")
|
|
self.assertIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
with self.assertNumQueries(0):
|
|
[list(book.first_time_authors.all()) for book in books]
|
|
|
|
books = list(Book.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(
|
|
books,
|
|
Prefetch(
|
|
"first_time_authors",
|
|
queryset=Author.objects.order_by("-name"),
|
|
),
|
|
)
|
|
self.assertIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
def test_one_to_one_forward(self):
|
|
houses = list(House.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(houses, "main_room")
|
|
self.assertNotIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
with self.assertNumQueries(0):
|
|
[house.main_room for house in houses]
|
|
|
|
houses = list(House.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(
|
|
houses,
|
|
Prefetch("main_room", queryset=Room.objects.order_by("-name")),
|
|
)
|
|
self.assertNotIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
def test_one_to_one_reverse(self):
|
|
rooms = list(Room.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(rooms, "main_room_of")
|
|
self.assertNotIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
with self.assertNumQueries(0):
|
|
[room.main_room_of for room in rooms]
|
|
|
|
rooms = list(Room.objects.all())
|
|
with self.assertNumQueries(1) as ctx:
|
|
prefetch_related_objects(
|
|
rooms,
|
|
Prefetch("main_room_of", queryset=House.objects.order_by("-name")),
|
|
)
|
|
self.assertNotIn("ORDER BY", ctx.captured_queries[0]["sql"])
|
|
|
|
def test_m2m_then_m2m(self):
|
|
"""A m2m can be followed through another m2m."""
|
|
authors = list(Author.objects.all())
|
|
with self.assertNumQueries(2):
|
|
prefetch_related_objects(authors, "books__read_by")
|
|
|
|
with self.assertNumQueries(0):
|
|
self.assertEqual(
|
|
[
|
|
[[str(r) for r in b.read_by.all()] for b in a.books.all()]
|
|
for a in authors
|
|
],
|
|
[
|
|
[["Amy"], ["Belinda"]], # Charlotte - Poems, Jane Eyre
|
|
[["Amy"]], # Anne - Poems
|
|
[["Amy"], []], # Emily - Poems, Wuthering Heights
|
|
[["Amy", "Belinda"]], # Jane - Sense and Sense
|
|
],
|
|
)
|
|
|
|
def test_prefetch_object(self):
|
|
book1 = Book.objects.get(id=self.book1.id)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects([book1], Prefetch("authors"))
|
|
|
|
with self.assertNumQueries(0):
|
|
self.assertCountEqual(
|
|
book1.authors.all(), [self.author1, self.author2, self.author3]
|
|
)
|
|
|
|
def test_prefetch_object_twice(self):
|
|
book1 = Book.objects.get(id=self.book1.id)
|
|
book2 = Book.objects.get(id=self.book2.id)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects([book1], Prefetch("authors"))
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects([book1, book2], Prefetch("authors"))
|
|
with self.assertNumQueries(0):
|
|
self.assertCountEqual(book2.authors.all(), [self.author1])
|
|
|
|
def test_prefetch_object_to_attr(self):
|
|
book1 = Book.objects.get(id=self.book1.id)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects(
|
|
[book1], Prefetch("authors", to_attr="the_authors")
|
|
)
|
|
|
|
with self.assertNumQueries(0):
|
|
self.assertCountEqual(
|
|
book1.the_authors, [self.author1, self.author2, self.author3]
|
|
)
|
|
|
|
def test_prefetch_object_to_attr_twice(self):
|
|
book1 = Book.objects.get(id=self.book1.id)
|
|
book2 = Book.objects.get(id=self.book2.id)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects(
|
|
[book1],
|
|
Prefetch("authors", to_attr="the_authors"),
|
|
)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects(
|
|
[book1, book2],
|
|
Prefetch("authors", to_attr="the_authors"),
|
|
)
|
|
with self.assertNumQueries(0):
|
|
self.assertCountEqual(book2.the_authors, [self.author1])
|
|
|
|
def test_prefetch_queryset(self):
|
|
book1 = Book.objects.get(id=self.book1.id)
|
|
with self.assertNumQueries(1):
|
|
prefetch_related_objects(
|
|
[book1],
|
|
Prefetch(
|
|
"authors",
|
|
queryset=Author.objects.filter(
|
|
id__in=[self.author1.id, self.author2.id]
|
|
),
|
|
),
|
|
)
|
|
|
|
with self.assertNumQueries(0):
|
|
self.assertCountEqual(book1.authors.all(), [self.author1, self.author2])
|