Well strictly speaking this isn't a business rule, it's a denormalization -- what deepa wants to do is store redundant data in a master table.

That aside, all that Oracle Corp. is saying here is that triggers can be used for the listed purposes.

Now personally i think that it's a bad idea to hide application-essential code in a trigger. If your application depends on it then put it in the application packages, where support and development staff can see exactly where the code fits into the application.