Method database_forwards

django/db/migrations/operations/fields.py:235–245

(self, app_label, schema_editor, from_state, to_state)

        )

    def database_forwards(self, app_label, schema_editor, from_state, to_state):
        to_model = to_state.apps.get_model(app_label, self.model_name)
        if self.allow_migrate_model(schema_editor.connection.alias, to_model):
            from_model = from_state.apps.get_model(app_label, self.model_name)
            from_field = from_model._meta.get_field(self.name)
            to_field = to_model._meta.get_field(self.name)
            if not self.preserve_default:
                to_field.default = self.field.default
            schema_editor.alter_field(from_model, from_field, to_field)
            if not self.preserve_default:
                to_field.default = NOT_PROVIDED

    def database_backwards(self, app_label, schema_editor, from_state, to_state):
        self.database_forwards(app_label, schema_editor, from_state, to_state)