Forms, database triggers, 3.0 to 5.0

Currently we are using Forms 3.0 and converting to 5.0.. It has come to our attention that no longer is it considered appropriate to incorporate database code within the form itself. We have been told that all code should be written at the database level and the only code in the forms should be form navigation code. Is this correct? Is it possible to write all the code in the database using stored procedures,functions, and triggers and keeping the forms relatively clean of code? This would involve moving all pre and post update and insert code from 3.0 forms to some sort of database triggers. Let me also say that we are having a big problem understanding and getting around this "mutating table" crap that never, ever surfaced when the code was in the form itself. Fishing for comments...

                                -Mark