python-sqlalchemy/sqlalchemy-1.4.0-group_by_joined_relations.patch
Lumir Balhar 7ba024caba Fix GROUP BY for joined relationships
Resolves: RHEL-17988
2023-12-04 14:08:27 +01:00

144 lines
5.5 KiB
Diff

From 2c71a8d17df6671fa0cde33d643c993a4317536d Mon Sep 17 00:00:00 2001
From: Lumir Balhar <lbalhar@redhat.com>
Date: Mon, 4 Dec 2023 13:33:29 +0100
Subject: [PATCH] Include GROUP BY in _should_nest_selectable criteria
Fixed bug where usage of joined eager loading would not properly wrap the
query inside of a subquery when :meth:`.Query.group_by` were used against
the query. When any kind of result-limiting approach is used, such as
DISTINCT, LIMIT, OFFSET, joined eager loading embeds the row-limited query
inside of a subquery so that the collection results are not impacted. For
some reason, the presence of GROUP BY was never included in this criterion,
even though it has a similar effect as using DISTINCT. Additionally, the
bug would prevent using GROUP BY at all for a joined eager load query for
most database platforms which forbid non-aggregated, non-grouped columns
from being in the query, as the additional columns for the joined eager
load would not be accepted by the database.
Fixes: #5065
Change-Id: I9a2ed8196f83297ec38012138d1a5acdf9e88155
---
lib/sqlalchemy/orm/query.py | 3 ++-
test/orm/test_eager_relations.py | 40 +++++++++++++++++++++++++++++
test/orm/test_subquery_relations.py | 39 ++++++++++++++++++++++++++++
3 files changed, 81 insertions(+), 1 deletion(-)
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index a17f590..bd0081f 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -3076,7 +3076,8 @@ class Query(object):
kwargs = self._select_args
return (kwargs.get('limit') is not None or
kwargs.get('offset') is not None or
- kwargs.get('distinct', False))
+ kwargs.get('distinct', False) or
+ kwargs.get("group_by", False))
def exists(self):
"""A convenience method that turns a query into an EXISTS subquery
diff --git a/test/orm/test_eager_relations.py b/test/orm/test_eager_relations.py
index 3c669d9..9aeeca5 100644
--- a/test/orm/test_eager_relations.py
+++ b/test/orm/test_eager_relations.py
@@ -747,6 +747,46 @@ class EagerTest(_fixtures.FixtureTest, testing.AssertsCompiledSQL):
eq_(self.static.user_address_result, result)
self.assert_sql_count(testing.db, go, 1)
+ def test_group_by_only(self):
+ # like distinct(), a group_by() has a similar effect so the
+ # joined eager load needs to subquery for this as well
+ users, Address, addresses, User = (
+ self.tables.users,
+ self.classes.Address,
+ self.tables.addresses,
+ self.classes.User,
+ )
+
+ mapper(
+ User,
+ users,
+ properties={
+ "addresses": relationship(
+ mapper(Address, addresses),
+ lazy="joined",
+ order_by=addresses.c.email_address,
+ )
+ },
+ )
+
+ q = create_session().query(User)
+ eq_(
+ [
+ User(id=7, addresses=[Address(id=1)]),
+ User(
+ id=8,
+ addresses=[
+ Address(id=3, email_address="ed@bettyboop.com"),
+ Address(id=4, email_address="ed@lala.com"),
+ Address(id=2, email_address="ed@wood.com"),
+ ],
+ ),
+ User(id=9, addresses=[Address(id=5)]),
+ User(id=10, addresses=[]),
+ ],
+ q.order_by(User.id).group_by(User).all(), # group by all columns
+ )
+
def test_limit_2(self):
keywords, items, item_keywords, Keyword, Item = (
self.tables.keywords,
diff --git a/test/orm/test_subquery_relations.py b/test/orm/test_subquery_relations.py
index 606beb5..aef9c34 100644
--- a/test/orm/test_subquery_relations.py
+++ b/test/orm/test_subquery_relations.py
@@ -754,6 +754,45 @@ class EagerTest(_fixtures.FixtureTest, testing.AssertsCompiledSQL):
result = q.limit(2).all()
eq_(result, list(reversed(self.static.user_address_result[2:4])))
+ def test_group_by_only(self):
+ # test group_by() not impacting results, similarly to joinedload
+ users, Address, addresses, User = (
+ self.tables.users,
+ self.classes.Address,
+ self.tables.addresses,
+ self.classes.User,
+ )
+
+ mapper(
+ User,
+ users,
+ properties={
+ "addresses": relationship(
+ mapper(Address, addresses),
+ lazy="subquery",
+ order_by=addresses.c.email_address,
+ )
+ },
+ )
+
+ q = create_session().query(User)
+ eq_(
+ [
+ User(id=7, addresses=[Address(id=1)]),
+ User(
+ id=8,
+ addresses=[
+ Address(id=3, email_address="ed@bettyboop.com"),
+ Address(id=4, email_address="ed@lala.com"),
+ Address(id=2, email_address="ed@wood.com"),
+ ],
+ ),
+ User(id=9, addresses=[Address(id=5)]),
+ User(id=10, addresses=[]),
+ ],
+ q.order_by(User.id).group_by(User).all(), # group by all columns
+ )
+
def test_one_to_many_scalar(self):
Address, addresses, users, User = (self.classes.Address,
self.tables.addresses,
--
2.43.0