PHP5.3利用PDO连接MSSQL2000，纠结好久，终于连接成功！
现将PDO成功连接MSSQL的步骤简要整理如下：
1、下载microsoft drivers for php for sql server（目前有2.0 3.0版本，分别又分有ts和nts版，可通过phpinfo()中的Thread Safety:enable确认是ts，详见驱动自带手册）
2、复制驱动至php文件夹的ext文件夹后，修改php.ini扩展extension=php_pdo_sqlsrv_53_ts_vc6.dll
3、下载Microsoft SQL Server 2008 R2 Native Client安装
测试代码：
try {
$hostname = "192.168.1.100";
$dbname = "Northwind";
$username = "sa";
$pwd = "pwd100";
$dsn="sqlsrv:Server=$hostname;database=$dbname";
$conn = new PDO ($dsn,$username,$pwd);
$conn->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
echo "mssql database connnection sucessed!";
} catch (PDOException $e) {
echo "Failed to get DB handle: " . $e->getMessage() . "n";
exit;
}
?>
