mysql数据库事件调度(Event)

mysql中的事件调度器可以定时对数据库增加,删除和执行操作,相当于数据库中的临时触发器,与Linux系统中的执行计划任务一样,这样就可以大大降低工作量.1.开启事件

mysql中的事件调度器可以定时对数据库增加,删除和执行操作,相当于数据库中的临时触发器,与Linux系统中的执行计划任务一样,这样就可以大大降低工作量.

1.开启事件调度器

[root@node1 ~]# vim /usr/my.cnf --在配置文件中加入以下语句启用调度器

event_scheduler=1

[root@node1 ~]# /etc/init.d/mysql restart
ERROR! MySQL server PID file could not be found!
Starting MySQL... SUCCESS!

[root@node1 ~]#

2.查看事件调度是否开启

[root@node1 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.21 MySQL Community Server (GPL)

Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show variables like "event_%"; --查看调度器是否启用
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| event_scheduler | ON |
+-----------------+-------+
1 row in set (0.00 sec)

mysql> ? create event; --查看创建事件的语法
Name: 'CREATE EVENT'
Description:
Syntax:
CREATE
[DEFINER = { user | CURRENT_USER }]
EVENT
[IF NOT EXISTS]
event_name
ON SCHEDULE schedule
[ON COMPLETION [NOT] PRESERVE]
[ENABLE | DISABLE | DISABLE ON SLAVE]
[COMMENT 'comment']
DO event_body;

schedule:
AT timestamp [+ INTERVAL interval] ...
| EVERY interval
[STARTS timestamp [+ INTERVAL interval] ...]
[ENDS timestamp [+ INTERVAL interval] ...]

interval:
quantity {YEAR | QUARTER | MONTH | DAY | HOUR | MINUTE |
WEEK | SECOND | YEAR_MONTH | DAY_HOUR | DAY_MINUTE |
DAY_SECOND | HOUR_MINUTE | HOUR_SECOND | MINUTE_SECOND}
mysql> create database test123;
Query OK, 1 row affected (0.00 sec)
mysql> \u test123
Database changed

mysql>

3.创建事件调度5秒钟后创建t表

mysql> create event if not exists event_t on schedule at current_timestamp + interval 5 second do create table t (a int,b nchar(10),c timestamp);
Query OK, 0 rows affected (0.00 sec)

mysql> show events; --查看事件是否创建成功
+---------+----------+----------------+-----------+-----------+------------+----------------+----------------+---------------------+------+---------+------------+----------------------+----------------------+--------------------+
| Db | Name | Definer | Time zone | Type | Execute at | Interval value | Interval field | Starts | Ends | Status | Originator | character_set_client | collation_connection | Database Collation |
+---------+----------+----------------+-----------+-----------+------------+----------------+----------------+---------------------+------+---------+------------+----------------------+----------------------+--------------------+
| test123 | event_t1 | root@localhost | SYSTEM | RECURRING | NULL | 5 | SECOND | 2014-11-12 15:29:13 | NULL | ENABLED | 0 | utf8 | utf8_general_ci | latin1_swedish_ci |
+---------+----------+----------------+-----------+-----------+------------+----------------+----------------+---------------------+------+---------+------------+----------------------+----------------------+--------------------+
1 row in set (0.00 sec)

mysql> show tables;
Empty set (0.00 sec)

mysql> show tables; --创建表成功
+-------------------+
| Tables_in_test123 |
+-------------------+
| t |
+-------------------+
1 row in set (0.00 sec)