Triggers - How expensive when set on heavily loaded tables ?

Qs 1) Whenever an Account ID is transacted - INSERT occurs into a table TRAN_TBL as part of the transaction , Additionally the Account ID is checked for existence in another table say TABLE_1 . If found , a record is inserted into yet another table say TABLE_2 .  

Qs. Operations involving TABLE_1 & TABLE_2 if managed using triggers , How expensive in CPU & performance will it be ?

NOTE - TRAN_TBL undergoes very large volumes of Concurrent OLTP INSERT transaction .

Qs 2) If an alert is to be raised on addition of a new record to TABLE_2 :- a) Can trigger be used ?
b) Should a cron job running every 5 min. look at TABLE_2 & based on the time criteria generates the alert ?

Thanks Received on Wed Jul 23 2003 - 22:11:31 CDT