MySQL 建表自动添加当前系统时间

mysql>create table timetest(

->id int not null,

->modtime timestamp default current_timestamp on update current_timestamp,

->primary key(id)

->)engine=innodb,default charset=utf8

Query OK, 0 rows affected (0.06 sec)

以下是测试，包括建表时记录时间，插入时记录时间，更新时记录时间：

mysql>insert into timetest(id) values (1),(2),(3)

Query OK, 3 rows affected (0.06 sec)

Records: 3 Duplicates: 0 Warnings: 0

mysql>select * from timetest

+----+---------------------+

| id | modtime |

+----+---------------------+

| 1 | 2011-09-21 09:56:24 |

| 2 | 2011-09-21 09:56:24 |

| 3 | 2011-09-21 09:56:24 |

+----+---------------------+

3 rows in set (0.00 sec)

mysql>update timetest set id=10 where id=1

Query OK, 1 row affected (0.06 sec)

Rows matched: 1 Changed: 1 Warnings: 0

mysql>select * from timetest

+----+---------------------+

| id | modtime |

+----+---------------------+

| 2 | 2011-09-21 09:56:24 |

| 3 | 2011-09-21 09:56:24 |

| 10 | 2011-09-21 09:57:15 |

+----+---------------------+

3 rows in set (0.00 sec)

mysql>update timetest set id=4 where id=3

Query OK, 1 row affected (0.05 sec)

Rows matched: 1 Changed: 1 Warnings: 0

mysql>select * from timetest

+----+---------------------+

| id | modtime |

+----+---------------------+

| 2 | 2011-09-21 09:56:24 |

| 4 | 2011-09-21 09:58:10 |

| 10 | 2011-09-21 09:57:15 |

+----+---------------------+

3 rows in set (0.00 sec)

mysql>

我们在向表中插入数据的时候，如果表字段有类似于创建时间的字段，往往需要手动添加，特别的麻烦。我们只需要把时间字段设置成 timestamp 类型，然后把默认值设置为 CURRENT_TIMESTAMP 即可。这样在添加一条新数据的时候，该字段会自动生成当前时间，不需要再手动添加，非常的方便。

---