I have TableA which is transactional. TableB is basically a roll-up(sum of data and additional data) of TableA. Currently the application is inserting/updating both TableA and TableB. It is beyond my control and cannot stop the application from updating TableB however that's what I want to do. So the application is going to INSERT TableA, then UPDATE TableB but I want to make a trigger on TableA to update TableB correctly and when the application issues UPDATE TableB, I want it to do nothing.