SYbase ASAトリガ書き方、ある値が変更されたときに実行文をトリガする

ALTER TRIGGER "T" AFTER UPDATE OF "approved"
ORDER 3 ON "DBA"."shipper"
referencing new as new_shipper3
FOR EACH ROW /* WHEN(      ) */
 
BEGIN

case when   new_shipper3.approved='Y'  --     
then update DBA.customer set customer.user_7=customer.user_7-(shipper_line.quantity*isnull(part.user_10,0)) from  DBA.shipper,DBA.shipper_line,DBA.customer,DBA.part--      "DBA"
             where             new_shipper3.trans_no=shipper.trans_no and 
                               shipper.trans_no=shipper_line.trans_no and 
                             shipper.customer_id=customer.customer_id and
                                    shipper_line.part_id=part.part_id and 
                                                 part.product_code ='XQ'    
      when   new_shipper3.approved='N' 
then update Dba.customer set customer.user_7=customer.user_7+(shipper_line.quantity*isnull(part.user_10,0)) from dba.shipper,dba.shipper_line,dba.customer,dba.part --      "DBA"

          where             new_shipper3.trans_no=shipper.trans_no and 
                               shipper.trans_no=shipper_line.trans_no and 
                             shipper.customer_id=customer.customer_id and
                                    shipper_line.part_id=part.part_id and 
                                                 part.product_code ='XQ'   
else
  update shipper set
    edit_time = getdate(*) where
    shipper.trans_no = new_shipper3.trans_no
end case
end