检测MySQL数据库中更新的行是否已更改

I've got two fields, one that has the userID of the user that updated the record, and one timestamp field for the time of the last update. I have several different points where users enter data and I'm trying to figure out the best way to stop the userID and timestamp from being updated if the user keeps all of the information the same (the MySQL updates put in the same exact information that's already there).I've got two fields, one that has the userID of