From 534d8d875eebac6aee278f0ffa6cc59760dac546 Mon Sep 17 00:00:00 2001
From: Adnan Umer <u.adnan@outlook.com>
Date: Wed, 18 Apr 2018 22:30:25 +0500
Subject: [PATCH] Fixed #28600 -- Added prefetch_related() support to
RawQuerySet.
---
django/db/models/query.py | 30 ++++++++++++++++++++++++++-
docs/releases/2.1.txt | 2 ++
tests/prefetch_related/tests.py | 36 ++++++++++++++++++++++++++++++++-
3 files changed, 66 insertions(+), 2 deletions(-)
diff --git a/django/db/models/query.py b/django/db/models/query.py
index f16af1e91d..8d4c2d083c 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -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()
diff --git a/docs/releases/2.1.txt b/docs/releases/2.1.txt
index f3a99e5fc0..7595be46c0 100644
--- a/docs/releases/2.1.txt
+++ b/docs/releases/2.1.txt
@@ -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
~~~~~~~~~~~~~~~~~~~~~~
diff --git a/tests/prefetch_related/tests.py b/tests/prefetch_related/tests.py
index e92d7f349f..5a701bffec 100644
--- a/tests/prefetch_related/tests.py
+++ b/tests/prefetch_related/tests.py
@@ -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):