Siebel table query

Dear All,

Planning to deleted data in following tables periodically (i.e older than 30 days)

delete from S_WFA_INST_LOG where created < sysdate - 30;
delete from S_WFA_INSTP_LOG where created < sysdate - 30;
delete from S_WFA_STPRP_LOG where created < sysdate - 30;

Questions are

1) does the above 3 tables take into all workflow instance log related tables? or some other related table also exists which is missed here?2) is there any connection between the tables which needs to be considered ? like primary and foreign key ? or the above query is good enough.

3) what test cases you suggest to ensure this doesn't effect any existing functionalities