/**
  * Connect to the database.
  */
 function connect()
 {
     $this->db = mysql_db::getConnection();
     if (isset($this->config['database']['username']) && isset($this->config['database']['password'])) {
         if (!$this->db->connect($this->config['database'])) {
             $this->_err_code = 100;
             $this->_err_msg = 'Could not connect to database server';
         }
     }
 }