management.py 文件源码

def _rename(self, apps, schema_editor, old_model, new_model):
        ContentType = apps.get_model('contenttypes', 'ContentType')
        db = schema_editor.connection.alias
        if not router.allow_migrate_model(db, ContentType):
            return

        try:
            content_type = ContentType.objects.db_manager(db).get_by_natural_key(self.app_label, old_model)
        except ContentType.DoesNotExist:
            pass
        else:
            content_type.model = new_model
            try:
                with transaction.atomic(using=db):
                    content_type.save(update_fields={'model'})
            except IntegrityError:
                # Gracefully fallback if a stale content type causes a
                # conflict as update_contenttypes will take care of asking the
                # user what should be done next.
                content_type.model = old_model
            else:
                # Clear the cache as the `get_by_natual_key()` call will cache
                # the renamed ContentType instance by its old model name.
                ContentType.objects.clear_cache()