I have an inventory app, want to switch the back-end to MySQL, someone suggested me not to use calculated fields (eg: stock_OnHand) and replaced them with calculation by the fly.

(I have stock_OnHand field to record the balance, while his idea is throw away this field, just keep the transactions, anytime need it, calculated them with SQL statement).

I'm not sure about this, before I do a big change to my app, I would like to ask for second opinion, is this the way to do with MySQL?

regards,

Jerry