title: Exception to handle unpermitted DML-operation
body: <p>I'm trying to hinder a user who is not me from performing DML-operations on a table. I'm using a trigger but have some issues with the syntax. It is the "if user is not 'me' part that troubles me. Also, is stating "rollback;" enough to undo the operation? Thanks!</p>
  
  <pre><code>create or replace trigger only_me_ex
  before insert or update or delete on table
  for each row
  declare
  only_me_ex exception;
  begin
  if user is not 'me' then
  raise only_boss exception;
  end if;
  exception
  when only_me_ex then
  raise_appication_error(-200001,'Not permitted!');
  rollback;
  end;
  /
  </code></pre>