Hi
I would agree that cron is probably the best solution.
You could have cron perform a query that has a trigger and performs all the
tasks you need done. As well you could create a trigger on other queries that
would perform the other things as well, but make sure it isn't a heavily used
query but instead a query that is run hourly or daily. As a backup for cron
you could manualy or using "anacron" or somthing similar run the query cron
should run on a regular basis, but you should make sure your trigger keeps an
entry in your database letting the other queries know when the update is
started and when it has finished. Using this check ensures you don't get
"overlapping" updates, and can also give you a clue to how much time the
updates are taking and possibly alert you to a "hung" update.
Guy