Microsoft SQL Server Functions (PDO_SQLSRV)
相关介绍：http://php.net/manual/en/ref.pdo-sqlsrv.php
如：
Support for 5.5 has 4 drivers
php_pdo_sqlsrv_55_nts.dll
php_pdo_sqlsrv_55_ts.dll
php_sqlsrv_55_nts.dll
php_sqlsrv_55_ts.dll
各版本支持：
- Version 3.2 supports PHP 5.6, 5.5, and 5.4
- Version 3.1 supports PHP 5.5 and 5.4
- Version 3.0 supports PHP 5.4
这里下载：
http://www.microsoft.com/en-us/download/details.aspx?id=20098
