title: Prevent Insert Trigger
body: <p>How can I get this trigger to prevent the insert where the advance is not greater than 0 or less than 100? Thanks.</p>
  
  <pre><code>DROP TRIGGER CheckAdvance;
  CREATE OR REPLACE TRIGGER CheckAdvance
  BEFORE INSERT OR UPDATE OF advance ON titles
  FOR EACH ROW
  WHEN (new.advance&lt;0 OR new.advance&gt;100)
  BEGIN
  dbms_output.put_line('Advance is Invalid.');
  END;
  </code></pre>