Here is a simple php class for working with database. The problem with this class is in __destruct method, that launch mysql_close function. If I create two DB objects that are situated in code very close it cause an error. It looks like that mysql_close close all database connections, not just his own($this->dbLink). Why it is happens?

    require_once("modules/required/OptionsReader/m_OptionsReader.php");

    class DB{
        private $dbLink;

        public function  __construct() {
            $options = new OptionsReader();
            $DBSettings = $options->getDBSettings();
            $this->dbLink = mysql_connect($DBSettings->getAddress(),$DBSettings->getUserName(),$DBSettings->getPswd());
            @mysql_select_db($DBSettings->getDBName()) or die( "Unable to select database");
            mysql_query( "set names 'utf8'" );
        }

        public function  __destruct() {
            mysql_close($this->dbLink);
        }


        public function launchQuery($query){
            return mysql_query($query);
        }
    }
?>

P.S. Ben bu sorunun basit bir çözüm sadece __ desctuctor close () fonksiyonu yapmak ve elle başlatmak olduğunu biliyorum, ama ne olup bittiğini anlamak için harika olacak. Teşekkür ederim