mysql-sql CHECK约束无法正常工作
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了mysql-sql CHECK约束无法正常工作,小编现在分享给大家,供广大互联网技能从业者学习和参考。文章包含2153字,纯文字阅读大概需要4分钟。
内容图文
![mysql-sql CHECK约束无法正常工作](/upload/InfoBanner/zyjiaocheng/887/f8f5e1148d3a4189a7f66266673d4338.jpg)
这个问题已经在这里有了答案: > CHECK constraint in MySQL is not working 8个
我创建了带有检查约束的表计划:
mysql> create table schedule(order_date date, dely_date date
check(dely_date>order_date));
Query OK, 0 rows affected (0.50 sec)
当我插入违反检查约束的值时,sql报告没有错误.
mysql> insert into schedule values('2015-11-20','2014-12-25');
Query OK, 1 row affected (0.10 sec)
mysql> select * from schedule;
+------------+------------+
| order_date | dely_date |
+------------+------------+
| 2015-11-20 | 2014-12-25 |
+------------+------------+
1 row in set (0.00 sec)
我插入了一个在order_date之前的dely_date.
解决方法:
MySQL中的CHECK约束被忽略,如Jakub Kania's answer
使用SQL Server进行CHECK的示例:
create table #schedule(order_date date,
dely_date date,
check(dely_date>order_date));
insert into #schedule values('2015-11-20','2014-12-25');
-- The INSERT statement conflicted with the CHECK constraint "CK_#schedule_A59B8DED".
-- The conflict occurred in database "tempdb", table "dbo.#schedule___
-- __________________00000000C9D8". The statement has been terminated.
INSERT INTO #schedule values('2015-12-24','2015-12-25');
SELECT *
FROM #schedule;
您可以使用触发器进行验证:
CREATE TABLE `schedule`(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
order_date DATETIME,
dely_date DATETIME);
CREATE TRIGGER `schedule_trg_ins` BEFORE INSERT ON `schedule`
FOR EACH ROW
BEGIN
IF NOT(New.dely_date>New.order_date) THEN
SIGNAL SQLSTATE '10000'
SET MESSAGE_TEXT = 'check constraint on schedule failed during insert';
END IF;
END;
CREATE TRIGGER `schedule_trg_upd` BEFORE UPDATE ON `schedule`
FOR EACH ROW
BEGIN
IF NOT(New.dely_date>New.order_date) THEN
SIGNAL SQLSTATE '10000'
SET MESSAGE_TEXT = 'check constraint on schedule failed during update';
END IF;
END;
INSERT INTO `schedule`(order_date, dely_date)
VALUES ('2015-12-24','2015-12-25');
INSERT INTO `schedule`(order_date, dely_date)
VALUES ('2015-12-26','2015-12-25');
-- check constraint on schedule failed during insert
UPDATE `schedule`
SET order_date = '2015-12-26'
WHERE id = 1;
-- check constraint on schedule failed during update
内容总结
以上是互联网集市为您收集整理的mysql-sql CHECK约束无法正常工作全部内容,希望文章能够帮你解决mysql-sql CHECK约束无法正常工作所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错,欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 gblab@vip.qq.com 举报,一经查实,本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。