先来解释下什么是错误缓冲区?
- CREATE TABLE `t_datetime` (
- `id` int(11) NOT NULL,
- `log_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
- `end_time` datetime NOT NULL,
- PRIMARY KEY (`id`)
- ) ENGINE=InnoDB DEFAULT CHARSET=utf8
- DELIMITER $$
- USE `new_t`$$
- DROP PROCEDURE IF EXISTS `sp_do_update`$$
- CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_do_update`(
- IN f_id INT,
- IN f_log_time VARCHAR(255),
- IN f_end_time VARCHAR(255)
- )
- BEGIN
- DECLARE i_con1 TINYINT DEFAULT 0;
- DECLARE i_code CHAR(5) DEFAULT '00000';
- DECLARE i_msg TEXT;
- DECLARE i_rows INT;
- DECLARE i_con1 CONDITION FOR 1048; -- 这个错误代码代表字段限制不能NULL。
- DECLARE CONTINUE HANDLER FOR i_con1
- BEGIN
- SET i_con1 = 1;
- get diagnostics CONDITION 1
- i_code = returned_sqlstate, i_msg = message_text;
- END;
- UPDATE t_datetime
- SET log_time = IFNULL(f_log_time,NULL),
- end_time = IFNULL(f_end_time,NULL)
- WHERE id = f_id;
- IF i_con1 = 0 THEN
- get diagnostics i_rows = ROW_COUNT;
- SET @i_result = CONCAT("Update succeeded, affected ", i_rows,'.');
- ELSE
- SET @i_result = CONCAT('Update failed, error code is 1042, related message is ',i_msg,'.');
- END IF;
- SELECT @i_result;
- END$$
- DELIMITER ;
- CALL sp_do_update(1,NOW(),DATE_ADD(NOW(),INTERVAL 1 DAY));
- Result.
- Update succeeded, affected 1.
- CALL sp_do_update(1,NULL,NULL);
- Result.
- Update failed, error code is 1042, related message is Column 'log_time' cannot be null.