title: Updating only those fields which users have changed in a Form
body: <p>Lets say I have a form that contains 16 to 20 fields including input type texts and textareas.</p>
  
  <p>The form submits the fields using POST method to a php page which updates a table in a
  database with the $_POST vars. </p>
  
  <p>My Question is that I want to update the changed values only in the database rather than updating each and every value,</p>
  
  <p>How good is this approach to optimize the application? , also I read on another site the following answer: </p>
  
  <blockquote>
    <ul>
    <li>mySQL automatically detects that you're updating a field with the same value it already contains, and doesn't actually update that
    field. Not sure if this is the same for other databases thet can be
    used with php.</li>
    </ul>
  </blockquote>
  
  <p>also, how true is the above statement?</p>