业务场景:
例如用户表,我们需要建一个字段是创建时间, 一个字段是更新时间.
解决办法可以是指定插入时间,也可以使用数据库的默认时间.
在mysql中如果设置两个默认CURRENT_TIMESTAMP,会出现这样的错误.
ERROR 1293 (HY000): Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause.
错误的建表语句:
CREATE TABLE db1.sms_queue (
Id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
Message VARCHAR(160) NOT NULL DEFAULT ‘Unknown Message Error’,
CurrentState VARCHAR(10) NOT NULL DEFAULT ‘None’,
Phone VARCHAR(14) DEFAULT NULL,
Created TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
LastUpdated TIMESTAMP NOT NULL ON UPDATE CURRENT_TIMESTAMP,
TriesLeft tinyint NOT NULL DEFAULT 3,
PRIMARY KEY (Id)
)
ENGINE = InnoDB;
解决办法,可以使用触发器或者其他,在此还是使用数据库的方式.
建表语句:
create table test_table(
id integer not null auto_increment primary key,
stamp_created timestamp default ‘0000-00-00 00:00:00’,
stamp_updated timestamp default now() on update now()
);
测试:
mysql> insert into test_table(stamp_created, stamp_updated) values(null, null);Query OK, 1 row affected (0.06 sec)mysql> select * from t5;+----+---------------------+---------------------+ | id | stamp_created | stamp_updated |+----+---------------------+---------------------+| 2 | 2009-04-30 09:44:35 | 2009-04-30 09:44:35 |+----+---------------------+---------------------+2 rows in set (0.00 sec)mysql> update test_table set id = 3 where id = 2;Query OK, 1 row affected (0.05 sec) Rows matched: 1 Changed: 1 Warnings: 0mysql> select * from test_table;+----+---------------------+---------------------+| id | stamp_created | stamp_updated |+----+---------------------+---------------------+ | 3 | 2009-04-30 09:44:35 | 2009-04-30 09:46:59 |+----+---------------------+---------------------+ 2 rows in set (0.00 sec)
解决办法是在stackoverflow看到的,原文网址:
