PHP5.4连接sqlserver

<?php
header("Content-Type: text/html;charset=utf-8");

class mssql{
    private $host;
    private $username;
    private $password;
    private $database;
    private $handle;
    private function __construct (Array $config){
        $this -> host = $config[‘host‘];
        $this -> username = $config[‘username‘];
        $this -> password = $config[‘password‘];
        $this -> database = $config[‘database‘];
        $this -> init();
    }
    private function init() {
        $dsn = ‘sqlsrv:server = ‘.$this -> host.‘;database = ‘.$this->database;
        $this -> handle = new PDO($dsn,$this -> username, $this -> password);
    }
    public static function GetInstance(array $config = null) {
        if (null == $config) {
            return NULL;
        } 
        static $db = null;
        if (null == $db) {
            $c = __CLASS__;
            $db = new $c($config);
        };
        return $db -> handle;
    }
}

$config = array(
    ‘host‘ => ‘192.168.0.152,1433‘,
    ‘database‘ => ‘TimeTracker‘,
    ‘username‘ => ‘sa‘,
    ‘password‘ => ‘123‘
);
$mssql = mssql::GetInstance($config);
$result = $mssql->query(‘SELECT * FROM T_Sys_UserInfo‘);
foreach($result as  $row){
    echo $row[2];
}
?>