title: How to update after insert in the same table in an Oracle trigger?
body: <p>I have a table with columns X, Y and Z. I want to set Z when I insert or update X and Y, so Z=X*Y, using a trigger.</p>
  
  <pre><code>create or replace trigger tr_tab
  after insert
  on tab
  for each row
  begin
  update tab
  set z=x*y;
  end;
  /
  </code></pre>
  
  <p>But after insert I get an error. </p>