作者:圆季 | 来源:互联网 | 2018-06-12 11:05
想监控Bugzilla数据库中几个重要的表,如果它们发生了任何改变(增、删、改),都希望能够记录下来,以便后面再写程序来分析。很自然,就想到使用MySQL的触发器(Trigger)了,学习了一会,记录如下:1.先建立一个新的表用于记录我需要的变化:CREATETAB
想监控Bugzilla数据库中几个重要的表,如果它们发生了任何改变(增、删、改),都希望能够记录下来,以便后面再写程序来分析。很自然,就想到使用MySQL的触发器(Trigger)了,学习了一会,记录如下: 1. 先建立一个新的表用于记录我需要的变化: CREATE TAB
想监控Bugzilla数据库中几个重要的表,如果它们发生了任何改变(增、删、改),都希望能够记录下来,以便后面再写程序来分析。很自然,就想到使用MySQL的触发器(Trigger)了,学习了一会,记录如下:
1. 先建立一个新的表用于记录我需要的变化:
CREATE TABLE `bugzilla_log` (
`id` INT UNSIGNED NOT NULL,
`table` varchar(80) NOT NULL,
`action` ENUM('insert','update','delete'),
`ts` TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='logging some important changes in bugzilla DB';
2. 针对需要监控的表,创建触发器:
CREATE
TRIGGER `classifications_insert`
AFTER INSERT
ON classifications FOR EACH ROW
INSERT INTO `bugzilla_log` (`id`, `table`, `action`, `ts`) VALUES (NEW.id, 'classifications', 'insert', NOW());
?
CREATE
TRIGGER `classifications_update`
AFTER UPDATE
ON classifications FOR EACH ROW
INSERT INTO `bugzilla_log` (`id`, `table`, `action`, `ts`) VALUES (NEW.id, 'classifications', 'update', NOW());
?
CREATE
TRIGGER `classifications_delete`
BEFORE DELETE
ON classifications FOR EACH ROW
INSERT INTO `bugzilla_log` (`id`, `table`, `action`, `ts`) VALUES (OLD.id, 'classifications', 'delete', NOW());
请注意其中AFTER和BEFORE,以及OLD和NEW的使用。
Within the trigger body, you can refer to columns in the subject table (the table associated with the trigger) by using the aliases OLD and NEW. OLD.col_name refers to a column of an existing row before it is updated or deleted. NEW.col_name refers to the column of a new row to be inserted or an existing row after it is updated.
3. 查看当前数据库中的触发器:
SHOW TRIGGERS;
参考资料:
http://dev.mysql.com/doc/refman/5.5/en/create-trigger.html
http://www.jicdesign.com/blog/web-development/how-to-use-mysql-triggers-to-log-table-changes.html
Original article: 在MySQL中使用触发器Trigger的操作过程
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原文地址:在MySQL中使用触发器Trigger的操作过程, 感谢原作者分享。