public static function obtain($server = null, $user = null, $pass = null, $database = null, $pref = null)
    {
        if (null === self::$_instance) {
            self::$_instance = new db($server, $user, $pass, $database, $pref);
        }
        return self::$_instance;
    }
public static function obtain($server = null, $user = null, $pass = null, $database = null, $pref = null)
    {
        if (null === self::$_instance) {
            self::$_instance = new db($server, $user, $pass, $database, $pref);
        }
        return self::$_instance;
    }
public static function obtain ( $ server = null , $ user = null , $ pass = null , $ database = null , $ pref = null ) { if ( null === self :: $ _instance ) { self :: $ _instance = new db ( $ server , $ user , $ pass , $ database , $ pref ) ; } return self :: $ _instance ; }
Obtain an instance of Database object
@static
@param $server string
@param $user string
@param $pass string
@param $database string
@param $pref string
@return db If object does not exists create new and return else return already created object
Obtain an instance of Database object