MySQL資料庫事件調度(Event)
MySQL中的事件調度器可以定時對資料庫增加,刪除和執行操作,相當於資料庫中的臨時觸發器,與Linux系統中的執行計畫任務一樣,這樣就可以大大降低工作量。
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1.開啟事件調度器
[root@node1 ~]# vim /usr/my.cnf --在設定檔中加入以下語句啟用調度器
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.查看事件調度是否開啟
[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_%"; --查看調度器是否啟用
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| event_scheduler | ON |
+-----------------+-------+
1 row in set (0.00 sec)
mysql> ? create event; --查看建立事件的文法
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.建立事件調度5秒鐘後建立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; --查看事件是否建立成功
+---------+----------+----------------+-----------+-----------+------------+----------------+----------------+---------------------+------+---------+------------+----------------------+----------------------+--------------------+
| 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; --建立表成功
+-------------------+
| Tables_in_test123 |
+-------------------+
| t |
+-------------------+
1 row in set (0.00 sec)
mysql> desc t;
+-------+-----------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+-------------------+-----------------------------+
| a | int(11) | YES | | NULL | |
| b | char(10) | YES | | NULL | |
| c | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------+-----------+------+-----+-------------------+-----------------------------+
3 rows in set (0.01 sec)
mysql>
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