Fixed #24533 -- Dropped PostgreSQL sequence and Oracle identity when migrating away from AutoField.

1 files changed, 11 insertions, 0 deletions

diff --git a/django/db/backends/oracle/schema.py b/django/db/backends/oracle/schema.py
index d6585a80ca..002cb9e48b 100644
--- a/django/db/backends/oracle/schema.py
+++ b/django/db/backends/oracle/schema.py
@@ -122,6 +122,17 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
         # Rename and possibly make the new field NOT NULL
         super().alter_field(model, new_temp_field, new_field)
 
+    def _alter_column_type_sql(self, model, old_field, new_field, new_type):
+        auto_field_types = {'AutoField', 'BigAutoField', 'SmallAutoField'}
+        # Drop the identity if migrating away from AutoField.
+        if (
+            old_field.get_internal_type() in auto_field_types and
+            new_field.get_internal_type() not in auto_field_types and
+            self._is_identity_column(model._meta.db_table, new_field.column)
+        ):
+            self._drop_identity(model._meta.db_table, new_field.column)
+        return super()._alter_column_type_sql(model, old_field, new_field, new_type)
+
     def normalize_name(self, name):
         """
         Get the properly shortened and uppercased identifier as returned by