I have a simple billing table consisting of client's phone number, client's connect date, client's expire date, and client's balance.
"Samuel Jonhson" 2013-07-01 2013-09-01 8
I want to create a
trigger that checks if the client's balance is increased, and if it the client increased his balance, then the
trigger should prolong the expire date by adding monthes into expiration date according to client's balance where 4$ would be 1 month.