limit number of rows using a trigger
I want a (log) table to grow either for a certain number of rows or for a certain number of days. Then when I reach that limit, delete the oldest row before inserting a new. As with a roatating buffer.
As a test I made the following table:
delimiter $$
CREATE TABLE `a_test` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`a` int(11) NOT NULL DEFAULT '0',
`b` int(11) NOT NULL DEFAULT '0',
`last_update` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=latin1 MAX_ROWS=5$$
Then I made an attempt at the trigger
-- Trigger DDL Statements
DELIMITER $$
USE `test`$$
CREATE
DEFINER=`root`@`localhost`
TRIGGER `test`.`log_limit`
BEFORE INSERT ON `pgs`.`a_test`
FOR EACH ROW
BEGIN
SELECT COUNT(*) FROM a_test;
IF COUNT >= 5 THEN
DELETE FROM a_test ORDER BY last_update LIMIT 1;
END IF;
END$$
But I get this error:
SQL Error 1415: Not allowed to return a result set from a trigger
Edited 1 time(s). Last edit at 03/13/2012 03:55AM by Darren White.
Subject
Views
Written By
Posted
limit number of rows using a trigger
8320
March 13, 2012 03:50AM
2612
March 13, 2012 03:59AM
2039
March 13, 2012 04:09AM
2655
March 13, 2012 04:11AM
2257
March 13, 2012 11:50AM
1640
March 14, 2012 05:32AM
2547
March 14, 2012 11:48AM
Sorry, you can't reply to this topic. It has been closed.
Content reproduced on this site is the property of the respective copyright holders.
It is not reviewed in advance by Oracle and does not necessarily represent the opinion
of Oracle or any other party.