public function __construct($db_host, $db_port, $db_name, $db_user, $db_pswd)
 {
     parent::__construct($db_host, $db_port, $db_name, $db_user, $db_pswd);
     $this->ora_db_sid = $ora_db_sid;
     $this->ora_db_location = $ora_db_location;
 }
 public function __construct($db_host, $db_port, $db_name, $db_user, $db_pswd)
 {
     parent::__construct($db_host, $db_port, $db_name, $db_user, $db_pswd);
 }