title: $db = new DB() confusion
body: <p>Can any please explain what does it mean </p>
  
  <pre><code>$db = new DB(DB_DRIVER, DB_HOSTNAME, DB_USERNAME, DB_PASSWORD, DB_DATABASE);
  </code></pre>
  
  <p>and it's giving me an Error </p>
  
  <blockquote>
    <p>"Error: Could not load database file mysql!"</p>
  </blockquote>
  
  <p>file contents</p>
  
  <pre><code>define('DB_DRIVER', 'mysql');
  define('DB_HOSTNAME', 'localhost');
  define('DB_USERNAME', 'XXX');
  define('DB_PASSWORD', 'XXX');
  define('DB_DATABASE', 'XXXX');
  </code></pre>
  
  <p>DB CLASS Constructor</p>
  
  <pre><code>public function __construct($driver, $hostname, $username, $password, $database) {
  
          if (file_exists(DIR_DATABASE . $driver . '.php')) {
  
              require_once(DIR_DATABASE . $driver . '.php');
  
          } else {
  
              exit('Error: Could not load database file ' . $driver . '!');
  
          }
  
  
  
          $this-&gt;driver = new $driver($hostname, $username, $password, $database);
  
      }
  </code></pre>