From 560ff988dd6cff40381408c62494ca3eb9804f32 Mon Sep 17 00:00:00 2001
From: Simon Charette <charette.s@gmail.com>
Date: Sat, 13 Nov 2021 19:27:15 -0500
Subject: [PATCH] Refs #33288 -- Removed SQLite's
 DatabaseIntrospection._get_foreign_key_constraints().

The get_relations() method returns the exact same data in a more generic
format.
---
 django/db/backends/sqlite3/introspection.py | 29 +++++++++------------
 django/db/backends/sqlite3/schema.py        |  5 ++--
 2 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/django/db/backends/sqlite3/introspection.py b/django/db/backends/sqlite3/introspection.py
index 7c5c159b64..81884a7951 100644
--- a/django/db/backends/sqlite3/introspection.py
+++ b/django/db/backends/sqlite3/introspection.py
@@ -137,22 +137,6 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                 return name
         return None
 
-    def _get_foreign_key_constraints(self, cursor, table_name):
-        constraints = {}
-        cursor.execute('PRAGMA foreign_key_list(%s)' % self.connection.ops.quote_name(table_name))
-        for row in cursor.fetchall():
-            # Remaining on_update/on_delete/match values are of no interest.
-            id_, _, table, from_, to = row[:5]
-            constraints['fk_%d' % id_] = {
-                'columns': [from_],
-                'primary_key': False,
-                'unique': False,
-                'foreign_key': (table, to),
-                'check': False,
-                'index': False,
-            }
-        return constraints
-
     def _parse_column_or_constraint_definition(self, tokens, columns):
         token = None
         is_constraint_definition = None
@@ -349,7 +333,18 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                 "check": False,
                 "index": False,
             }
-        constraints.update(self._get_foreign_key_constraints(cursor, table_name))
+        relations = enumerate(self.get_relations(cursor, table_name).items())
+        constraints.update({
+            f'fk_{index}': {
+                'columns': [column_name],
+                'primary_key': False,
+                'unique': False,
+                'foreign_key': (ref_table_name, ref_column_name),
+                'check': False,
+                'index': False,
+            }
+            for index, (column_name, (ref_column_name, ref_table_name)) in relations
+        })
         return constraints
 
     def _get_index_columns_orders(self, sql):
diff --git a/django/db/backends/sqlite3/schema.py b/django/db/backends/sqlite3/schema.py
index f0c81c123b..db60fd4615 100644
--- a/django/db/backends/sqlite3/schema.py
+++ b/django/db/backends/sqlite3/schema.py
@@ -75,9 +75,8 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
             for other_table in self.connection.introspection.get_table_list(cursor):
                 if ignore_self and other_table.name == table_name:
                     continue
-                constraints = self.connection.introspection._get_foreign_key_constraints(cursor, other_table.name)
-                for constraint in constraints.values():
-                    constraint_table, constraint_column = constraint['foreign_key']
+                relations = self.connection.introspection.get_relations(cursor, other_table.name)
+                for constraint_column, constraint_table in relations.values():
                     if (constraint_table == table_name and
                             (column_name is None or constraint_column == column_name)):
                         return True