title: trigger oracle 16 age limit
body: <pre><code>CREATE OR REPLACE TRIGGER PREVENT16YRS  
  
  BEFORE INSERT OR UPDATE OF compno ON entry
  
  FOR EACH ROW
  BEGIN
  SELECT compdob
  from competitor
  where (2018 - EXTRACT(compdob) &lt; 16);
  raise raise_application_error( -20001, 'This is a custom error' );
  END;
  </code></pre>
  
  <p>Would like to restrict 16 years old from entering into entry table. But there's some syntax error in raising the application error. Some advise would be much appreciated thank you. :)</p>