sql CHECK 约束无法正常工作

Question

我已经创建了一个带有检查约束的 table 时间表：

mysql> create table schedule(order_date date, dely_date date
                             check(dely_date>order_date));
Query OK, 0 rows affected (0.50 sec)

当我插入一个违反检查约束的值时，sql 没有报告错误。

 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)

我在 order_date 之前插入了一个 dely_date。

Answer 1

哦，它工作正常。根据 manual:

The CHECK clause is parsed but ignored by all storage engines

您可能想尝试更理智的数据库。

Answer 2

MySQL 中的 CHECK 约束与

中一样被忽略

使用 SQL Server 工作 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;

LiveDemo

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

SqlFiddleDemo

sql CHECK 约束无法正常工作

sql CHECK constraint not working properly

mysql

sql

check-constraints