Method _execute_default

lib/sqlalchemy/engine/base.py:1466–1521

Execute a schema.ColumnDefault object.

(
        self,
        default: DefaultGenerator,
        distilled_parameters: _CoreMultiExecuteParams,
        execution_options: CoreExecuteOptionsParameter,
    )

        )

    def _execute_default(
        self,
        default: DefaultGenerator,
        distilled_parameters: _CoreMultiExecuteParams,
        execution_options: CoreExecuteOptionsParameter,
    ) -> Any:
        """Execute a schema.ColumnDefault object."""

        exec_opts = self._execution_options.merge_with(execution_options)

        event_multiparams: Optional[_CoreMultiExecuteParams]
        event_params: Optional[_CoreAnyExecuteParams]

        # note for event handlers, the "distilled parameters" which is always
        # a list of dicts is broken out into separate "multiparams" and
        # "params" collections, which allows the handler to distinguish
        # between an executemany and execute style set of parameters.
        if self._has_events or self.engine._has_events:
            (
                default,
                distilled_parameters,
                event_multiparams,
                event_params,
            ) = self._invoke_before_exec_event(
                default, distilled_parameters, exec_opts
            )
        else:
            event_multiparams = event_params = None

        try:
            conn = self._dbapi_connection
            if conn is None:
                conn = self._revalidate_connection()

            dialect = self.dialect
            ctx = dialect.execution_ctx_cls._init_default(
                dialect, self, conn, exec_opts
            )
        except (exc.PendingRollbackError, exc.ResourceClosedError):
            raise
        except BaseException as e:
            self._handle_dbapi_exception(e, None, None, None, None)

        ret = ctx._exec_default(None, default, None)

        if self._has_events or self.engine._has_events:
            self.dispatch.after_execute(
                self,
                default,
                event_multiparams,
                event_params,
                exec_opts,
                ret,
            )

        return ret

    def _execute_ddl(