A timer is probably the way to go but interferes with the running of your app. You could put the timer and table reading on another thread using SharedObjectRegister() etc. What happens then depends on what you have to do - process it in the background or do something to the interface to notify the user that action is required.
It's a shame the threading capabilities of PB are implemented in such an 'obscure' fashion because if you can get to grips with it, it works well. I used this technique years ago (PB8) to interface to a real time stock market feed.
HTH Paul