Used AND, OR, XOR constants instead of hard-coded values.

django/db/models/sql/compiler.py

@@ -19,6 +19,7 @@ from django.db.models.sql.constants import (
     SINGLE,
 )
 from django.db.models.sql.query import Query, get_order_dir
+from django.db.models.sql.where import AND
 from django.db.transaction import TransactionManagementError
 from django.utils.functional import cached_property
 from django.utils.hashable import make_hashable
@@ -1435,7 +1436,7 @@ class SQLCompiler:
         for index, select_col in enumerate(self.query.select):
             lhs_sql, lhs_params = self.compile(select_col)
             rhs = "%s.%s" % (qn(alias), qn2(columns[index]))
-            self.query.where.add(RawSQL("%s = %s" % (lhs_sql, rhs), lhs_params), "AND")
+            self.query.where.add(RawSQL("%s = %s" % (lhs_sql, rhs), lhs_params), AND)
 
         sql, params = self.as_sql()
         return "EXISTS (%s)" % sql, params

django/db/models/sql/query.py

@@ -2658,7 +2658,7 @@ class JoinPromoter:
             # to rel_a would remove a valid match from the query. So, we need
             # to promote any existing INNER to LOUTER (it is possible this
             # promotion in turn will be demoted later on).
-            if self.effective_connector == "OR" and votes < self.num_children:
+            if self.effective_connector == OR and votes < self.num_children:
                 to_promote.add(table)
             # If connector is AND and there is a filter that can match only
             # when there is a joinable row, then use INNER. For example, in
@@ -2670,8 +2670,8 @@ class JoinPromoter:
             #     (rel_a__col__icontains=Alex | rel_a__col__icontains=Russell)
             # then if rel_a doesn't produce any rows, the whole condition
             # can't match. Hence we can safely use INNER join.
-            if self.effective_connector == "AND" or (
+            if self.effective_connector == AND or (
-                self.effective_connector == "OR" and votes == self.num_children
+                self.effective_connector == OR and votes == self.num_children
             ):
                 to_demote.add(table)
             # Finally, what happens in cases where we have:

tests/queries/test_q.py

@@ -114,7 +114,7 @@ class QTests(SimpleTestCase):
                 ("price", F("discounted_price")),
             ),
         )
-        self.assertEqual(kwargs, {"_connector": "OR"})
+        self.assertEqual(kwargs, {"_connector": Q.OR})
 
     def test_deconstruct_xor(self):
         q1 = Q(price__gt=F("discounted_price"))
@@ -128,7 +128,7 @@ class QTests(SimpleTestCase):
                 ("price", F("discounted_price")),
             ),
         )
-        self.assertEqual(kwargs, {"_connector": "XOR"})
+        self.assertEqual(kwargs, {"_connector": Q.XOR})
 
     def test_deconstruct_and(self):
         q1 = Q(price__gt=F("discounted_price"))

tests/queries/test_query.py

@@ -16,7 +16,7 @@ from django.db.models.functions import Lower
 from django.db.models.lookups import Exact, GreaterThan, IsNull, LessThan
 from django.db.models.sql.constants import SINGLE
 from django.db.models.sql.query import JoinPromoter, Query, get_field_names_from_opts
-from django.db.models.sql.where import OR
+from django.db.models.sql.where import AND, OR
 from django.test import SimpleTestCase, TestCase, skipUnlessDBFeature
 from django.test.utils import register_lookup
 
@@ -214,6 +214,6 @@ class TestQueryNoModel(TestCase):
 class JoinPromoterTest(SimpleTestCase):
     def test_repr(self):
         self.assertEqual(
-            repr(JoinPromoter("AND", 3, True)),
+            repr(JoinPromoter(AND, 3, True)),
             "JoinPromoter(connector='AND', num_children=3, negated=True)",
         )

tests/queries/tests.py

@@ -10,7 +10,7 @@ from django.db import DEFAULT_DB_ALIAS, connection
 from django.db.models import Count, Exists, F, Max, OuterRef, Q
 from django.db.models.expressions import RawSQL
 from django.db.models.sql.constants import LOUTER
-from django.db.models.sql.where import NothingNode, WhereNode
+from django.db.models.sql.where import AND, OR, NothingNode, WhereNode
 from django.test import SimpleTestCase, TestCase, skipUnlessDBFeature
 from django.test.utils import CaptureQueriesContext, ignore_warnings
 from django.utils.deprecation import RemovedInDjango50Warning
@@ -3559,16 +3559,16 @@ class WhereNodeTest(SimpleTestCase):
 
     def test_empty_full_handling_disjunction(self):
         compiler = WhereNodeTest.MockCompiler()
-        w = WhereNode(children=[NothingNode()], connector="OR")
+        w = WhereNode(children=[NothingNode()], connector=OR)
         with self.assertRaises(EmptyResultSet):
             w.as_sql(compiler, connection)
         w.negate()
         self.assertEqual(w.as_sql(compiler, connection), ("", []))
-        w = WhereNode(children=[self.DummyNode(), self.DummyNode()], connector="OR")
+        w = WhereNode(children=[self.DummyNode(), self.DummyNode()], connector=OR)
         self.assertEqual(w.as_sql(compiler, connection), ("(dummy OR dummy)", []))
         w.negate()
         self.assertEqual(w.as_sql(compiler, connection), ("NOT (dummy OR dummy)", []))
-        w = WhereNode(children=[NothingNode(), self.DummyNode()], connector="OR")
+        w = WhereNode(children=[NothingNode(), self.DummyNode()], connector=OR)
         self.assertEqual(w.as_sql(compiler, connection), ("dummy", []))
         w.negate()
         self.assertEqual(w.as_sql(compiler, connection), ("NOT (dummy)", []))
@@ -3581,14 +3581,14 @@ class WhereNodeTest(SimpleTestCase):
         w.negate()
         with self.assertRaises(EmptyResultSet):
             w.as_sql(compiler, connection)
-        w.connector = "OR"
+        w.connector = OR
         with self.assertRaises(EmptyResultSet):
             w.as_sql(compiler, connection)
         w.negate()
         self.assertEqual(w.as_sql(compiler, connection), ("", []))
-        w = WhereNode(children=[empty_w, NothingNode()], connector="OR")
+        w = WhereNode(children=[empty_w, NothingNode()], connector=OR)
         self.assertEqual(w.as_sql(compiler, connection), ("", []))
-        w = WhereNode(children=[empty_w, NothingNode()], connector="AND")
+        w = WhereNode(children=[empty_w, NothingNode()], connector=AND)
         with self.assertRaises(EmptyResultSet):
             w.as_sql(compiler, connection)
 

tests/utils_tests/test_tree.py

@@ -1,6 +1,7 @@
 import copy
 import unittest
 
+from django.db.models.sql import AND, OR
 from django.utils.tree import Node
 
 
@@ -56,9 +57,9 @@ class NodeTests(unittest.TestCase):
         self.assertEqual(str(node3), "(DEFAULT: ('a', 1), ('b', 2), ('c', 3))")
 
     def test_add_eq_child_mixed_connector(self):
-        node = Node(["a", "b"], "OR")
+        node = Node(["a", "b"], OR)
-        self.assertEqual(node.add("a", "AND"), "a")
+        self.assertEqual(node.add("a", AND), "a")
-        self.assertEqual(node, Node([Node(["a", "b"], "OR"), "a"], "AND"))
+        self.assertEqual(node, Node([Node(["a", "b"], OR), "a"], AND))
 
     def test_negate(self):
         # negated is False by default