Log transaction for audit

Hi, I'm writing an application that requires log every transactions users done, e.g. update which record, delete which record, something like that. I guess one way is whenever I issue a mysql_query(), I also insert this query in whole into another table together with the user name, so I can log and retrieve it out for audit. Will you have that kind of experience? How can I do it comprehensively, e.g. no too big additional coding effort, easy to manage, reliable, etc. I'm using MySQL. Thank for your sharing, Yw