9,mysql触发器

1,触发器是由MYSQL的基本命令事件来触发某种特定操作，

触发器有两个重要因素:一是Action（动作）二是Condition（条件）

触发器就是在满足Conditoin条件时执行相应的动作，这个动作就是一系列的SQL语句

2，创建触发器

mysql> create trigger autolog before insert
    -> on user for each row
    -> insert into logtime values(null,now());
    -> //
Query OK, 0 rows affected (0.12 sec)

mysql> insert into user values(null,'123','123',now())//
Query OK, 1 row affected (0.06 sec)

mysql> select * from logtime;
    -> //
+----+---------------------+
| id | savetime            |
+----+---------------------+
|  1 | 2012-11-05 18:35:02 |
+----+---------------------+
1 row in set (0.00 sec)

3,查看所有的触发器

mysql> show triggers
    -> //
+---------+--------+-------+----------------------------------------+--------+---------+------------
----------------------------------------------------+----------------+----------------------+-------
---------------+--------------------+
| Trigger | Event  | Table | Statement                              | Timing | Created | sql_mode
                                                    | Definer        | character_set_client | collat
ion_connection | Database Collation |
+---------+--------+-------+----------------------------------------+--------+---------+------------
----------------------------------------------------+----------------+----------------------+-------
---------------+--------------------+
| autolog | INSERT | user  | insert into logtime values(null,now()) | BEFORE | NULL    | STRICT_TRAN
S_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION | root@localhost | utf8                 | utf8_g
eneral_ci      | utf8_general_ci    |
+---------+--------+-------+----------------------------------------+--------+---------+------------
----------------------------------------------------+----------------+----------------------+-------
---------------+--------------------+
1 row in set (0.01 sec)

4,删除触发器

mysql> drop trigger autolog//
Query OK, 0 rows affected (0.01 sec)