MySQL - Fastest way to check if data in InnoDB table has changed

Question

My application is very database intensive. Currently, I\'m running MySQL 5.5.19 and using MyISAM, but I\'m in the process of migrating to InnoDB. The only problem left is checks

Answer 1

The simplest way is to add a nullable column with type TIMESTAMP, with the trigger: ON UPDATE CURRENT_TIMESTAMP.

Therefore, the inserts will not change because the column accepts nulls, and you can select only new and changed columns by saying:

SELECT * FROM `table` WHERE `mdate` > '2011-12-21 12:31:22'

Every time you update a row this column will change automatically.

Here are some more informations: http://dev.mysql.com/doc/refman/5.0/en/timestamp.html

To see deleted rows simply create a trigger which is going to log every deletion to another table:

DELIMITER $$
CREATE TRIGGER MyTable_Trigger
AFTER DELETE ON MyTable
FOR EACH ROW
BEGIN
    INSERT INTO MyTable_Deleted VALUES(OLD.id, NOW());
END$$