title: Generate voluntary error for Materialized View update test
body: <p>Good night friends,</p>
  <p>I am creating a script to send mail when the update of the materialized view does not update correctly.</p>
  <p>How can I make a simple test script, create a script that generates an error in an intensional way to validate that the sending of mail is working when the specific update error is triggered.</p>
  <pre><code>CREATE MATERIALIZED VIEW emp_mv
  REFRESH COMPLETE
  ON DEMAND
  
  AS
      SELECT * FROM XXXXX;
  </code></pre>
  <p>generate error when executing the update.</p>
  <p>exec DBMS_MVIEW.REFRESH('emp_mv');</p>
  <p>thanks,</p>