Table update validation

hi,

i want to add  validation on table update , but  i want this method to be called only when i update existing record, not  when i insert.

i  added validation  on  validateWrite  method ,  i check there  before super  if    rec id  is  0  , so i know it is update or insert .

is there   any  method that  is called  strictly on update ?

ichecked validateWrite  and aosvalidateUpdate, they are both called on inserting record