Endless cycle in inserting/updating tables

Hi All,
I have 3 tables tab1,tab2,tab3. Each table has a trigger that will update or insert the other 2
Tab1 when inserting inserts into tab2 and tab3. Tab2 when inserting inserts into tab1 and tab3. Tab3 when inserting inserts into tab1 and tab2

As you can see this would result in endless loop.

Does anyone have any suggestions on how to solve?

Also if a table has a foreign constraint and a before insert/update trigger what is done first on insert
or update? Is the RI constraint checked first or is the trigger fired first. I have a situation if the RI
constraint fails I want to insert a record into another table so the foreign key constraint does not fail Received on Fri Oct 13 2000 - 08:04:34 CDT