LISTING 1: The AFTER Trigger

CREATE TRIGGER AFTER_UPDATE_TITLES
ON titles
FOR update
AS

-- We will assume that more than one row could have been updated.
-- The inserted and deleted tables will have to be joined on their
-- primary key, so we can't allow changes to the primary key.
IF @@rowcount = 0 RETURN
IF UPDATE(title_id) BEGIN
  PRINT 'updates to primary key title_id are not allowed'
  ROLLBACK TRAN
  RETURN
END

IF UPDATE (price)
   IF (SELECT MAX(ABS((i.price - d.price)*100/d.price))
	FROM inserted i JOIN deleted d
	   ON i.title_id = d.title_id)  > 10
  BEGIN 
	PRINT 'Too big of a price change'
	ROLLBACK TRAN
	RETURN
  END