public static function executeQuery($db_name, $params = array())
 {
     $instance = new self();
     $db =& $instance->GetDb();
     $query = 'SELECT * FROM ' . cms_db_prefix() . $db_name;
     $values = array();
     if (isset($params['where'])) {
         $fields = array();
         foreach ($params['where'] as $field => $value) {
             $fields[] = $field . ' =  ?';
             $values[] = $value;
         }
         $query .= ' WHERE ' . implode(' AND ', $fields);
     }
     if (isset($params['order_by'])) {
         $query .= ' ORDER BY ' . implode(', ', $params['order_by']);
     } else {
         $query .= ' ORDER BY position';
     }
     return $db->Execute($query, $values);
 }