title: Oracle trigger to update phone numbers
body: <p>Phone numbers are sent to our DB from a web service in this format:</p>
  
  <pre><code>1-210-5551212
  </code></pre>
  
  <p>I'd like for them to be input into the field like this if the first two characters are '1-':</p>
  
  <pre><code>1-210-555-1212
  </code></pre>
  
  <p>How would I create a on insert or update trigger to accomplish this?</p>