title: Increment a counter in database
body: <p>I need to set a counter for the visitor of each page.
  the script for protect link
  this is example for link
  <a href="http://www.science-union.com/upload/m1.php?id=356" rel="nofollow">http://www.science-union.com/upload/m1.php?id=356</a></p>
  
  <p>The database contains a table <code>data</code>.</p>
  
  <p>The table contains 5 fields for all links:</p>
  
  <ul>
  <li>id</li>
  <li>title</li>
  <li>url</li>
  <li>size</li>
  <li>email</li>
  </ul>
  
  <p>I added a new field and renamed it to <code>download</code> and fetched it in PHP file but it still shows <code>0</code>.
  look in example
  before Download button
  I need to php code  increase the download number for every visitor of the page.</p>