Fixed #28600 -- Added prefetch_related() support to RawQuerySet.

This commit is contained in:
Adnan Umer 2018-04-18 22:30:25 +05:00 committed by Tim Graham
parent f2026ca5e2
commit 534d8d875e
3 changed files with 66 additions and 2 deletions

View File

@ -727,7 +727,9 @@ class QuerySet:
def raw(self, raw_query, params=None, translations=None, using=None):
if using is None:
using = self.db
return RawQuerySet(raw_query, model=self.model, params=params, translations=translations, using=using)
qs = RawQuerySet(raw_query, model=self.model, params=params, translations=translations, using=using)
qs._prefetch_related_lookups = self._prefetch_related_lookups[:]
return qs
def _values(self, *fields, **expressions):
clone = self._chain()
@ -1278,6 +1280,8 @@ class RawQuerySet:
self.params = params or ()
self.translations = translations or {}
self._result_cache = None
self._prefetch_related_lookups = ()
self._prefetch_done = False
def resolve_model_init_order(self):
"""Resolve the init field names and value positions."""
@ -1289,9 +1293,33 @@ class RawQuerySet:
model_init_names = [f.attname for f in model_init_fields]
return model_init_names, model_init_order, annotation_fields
def prefetch_related(self, *lookups):
"""Same as QuerySet.prefetch_related()"""
clone = self._clone()
if lookups == (None,):
clone._prefetch_related_lookups = ()
else:
clone._prefetch_related_lookups = clone._prefetch_related_lookups + lookups
return clone
def _prefetch_related_objects(self):
prefetch_related_objects(self._result_cache, *self._prefetch_related_lookups)
self._prefetch_done = True
def _clone(self):
"""Same as QuerySet._clone()"""
c = self.__class__(
self.raw_query, model=self.model, query=self.query, params=self.params,
translations=self.translations, using=self._db, hints=self._hints
)
c._prefetch_related_lookups = self._prefetch_related_lookups[:]
return c
def _fetch_all(self):
if self._result_cache is None:
self._result_cache = list(self.iterator())
if self._prefetch_related_lookups and not self._prefetch_done:
self._prefetch_related_objects()
def __len__(self):
self._fetch_all()

View File

@ -239,6 +239,8 @@ Models
* The new :meth:`.QuerySet.explain` method displays the database's execution
plan of a queryset's query.
* :meth:`.QuerySet.raw` now supports :meth:`~.QuerySet.prefetch_related`.
Requests and Responses
~~~~~~~~~~~~~~~~~~~~~~

View File

@ -14,7 +14,7 @@ from .models import (
)
class PrefetchRelatedTests(TestCase):
class TestDataMixin:
@classmethod
def setUpTestData(cls):
cls.book1 = Book.objects.create(title='Poems')
@ -38,6 +38,8 @@ class PrefetchRelatedTests(TestCase):
cls.reader1.books_read.add(cls.book1, cls.book4)
cls.reader2.books_read.add(cls.book2, cls.book4)
class PrefetchRelatedTests(TestDataMixin, TestCase):
def assertWhereContains(self, sql, needle):
where_idx = sql.index('WHERE')
self.assertEqual(
@ -281,6 +283,38 @@ class PrefetchRelatedTests(TestCase):
self.assertWhereContains(sql, self.author1.id)
class RawQuerySetTests(TestDataMixin, TestCase):
def test_basic(self):
with self.assertNumQueries(2):
books = Book.objects.raw(
"SELECT * FROM prefetch_related_book WHERE id = %s",
(self.book1.id,)
).prefetch_related('authors')
book1 = list(books)[0]
with self.assertNumQueries(0):
self.assertCountEqual(book1.authors.all(), [self.author1, self.author2, self.author3])
def test_prefetch_before_raw(self):
with self.assertNumQueries(2):
books = Book.objects.prefetch_related('authors').raw(
"SELECT * FROM prefetch_related_book WHERE id = %s",
(self.book1.id,)
)
book1 = list(books)[0]
with self.assertNumQueries(0):
self.assertCountEqual(book1.authors.all(), [self.author1, self.author2, self.author3])
def test_clear(self):
with self.assertNumQueries(5):
with_prefetch = Author.objects.raw(
"SELECT * FROM prefetch_related_author"
).prefetch_related('books')
without_prefetch = with_prefetch.prefetch_related(None)
[list(a.books.all()) for a in without_prefetch]
class CustomPrefetchTests(TestCase):
@classmethod
def traverse_qs(cls, obj_iter, path):