# Microsoft SQL Server and Sybase Functions (PDO_DBLIB)

## Introduction

Warning

This extension is EXPERIMENTAL. The behaviour of this extension -- including the names of its functions and anything else documented about this extension -- may change without notice in a future release of PHP. Use this extension at your own risk.

PDO_DBLIB is a driver that implements the PHP Data Objects (PDO) interface to enable access from PHP to Microsoft SQL Server and Sybase databases through the FreeTDS libary.

On Windows, you should use the PDO_ODBC driver to connect to Microsoft SQL Server and Sybase databases, as the native Windows DB-LIB is ancient, thread un-safe and no longer supported by Microsoft.