Refs #29928 -- Implemented fast constraint checking on SQLite 3.20+.

django/db/backends/sqlite3/base.py

@@ -8,6 +8,7 @@ import math
 import operator
 import re
 import warnings
+from itertools import chain
 from sqlite3 import dbapi2 as Database
 
 import pytz
@@ -266,6 +267,37 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         determine if rows with invalid references were entered while constraint
         checks were off.
         """
+        if Database.sqlite_version_info >= (3, 20, 0):
+            with self.cursor() as cursor:
+                if table_names is None:
+                    violations = self.cursor().execute('PRAGMA foreign_key_check').fetchall()
+                else:
+                    violations = chain.from_iterable(
+                        cursor.execute('PRAGMA foreign_key_check(%s)' % table_name).fetchall()
+                        for table_name in table_names
+                    )
+                # See https://www.sqlite.org/pragma.html#pragma_foreign_key_check
+                for table_name, rowid, referenced_table_name, foreign_key_index in violations:
+                    foreign_key = cursor.execute(
+                        'PRAGMA foreign_key_list(%s)' % table_name
+                    ).fetchall()[foreign_key_index]
+                    column_name, referenced_column_name = foreign_key[3:5]
+                    primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
+                    primary_key_value, bad_value = cursor.execute(
+                        'SELECT %s, %s FROM %s WHERE rowid = %%s' % (
+                            primary_key_column_name, column_name, table_name
+                        ),
+                        (rowid,),
+                    ).fetchone()
+                    raise utils.IntegrityError(
+                        "The row in table '%s' with primary key '%s' has an "
+                        "invalid foreign key: %s.%s contains a value '%s' that "
+                        "does not have a corresponding value in %s.%s." % (
+                            table_name, primary_key_value, table_name, column_name,
+                            bad_value, referenced_table_name, referenced_column_name
+                        )
+                    )
+        else:
             with self.cursor() as cursor:
                 if table_names is None:
                     table_names = self.introspection.table_names(cursor)