A driver is software that allows your computer to communicate with hardware, devices or other software. Without drivers, the software or hardware you connect to your computer will not work properly.

Here is the list of the drivers which are available for SQL Server to connect from multiple applications and programming language.

Microsoft JDBC Driver 4.0 for SQL Server
The JDBC driver can access many of the features including database mirroring; the xml, user-defined, and large-value data types; and it supports the new “snapshot” transaction isolation.

Microsoft Drivers for PHP for SQL Server
The Microsoft Drivers for PHP for SQL Server API includes support for Windows Authentication, transactions, parameter binding, streaming, metadata access, and error handling.

Microsoft ODBC Driver for SQL Server
The Microsoft ODBC Driver for SQL Server is comprised of an ODBC driver for Windows and an ODBC driver for Linux.

Microsoft OLE DB Provider for DB2 Version 4.0
The Data Provider takes advantage of Microsoft SQL Server data access architecture together with a Microsoft network client for DB2 that functions as a Distributed Relational Database Architecture (DRDA) application requester. The Data Provider converts the Microsoft Component Object Model (COM) OLE DB commands and data types to DRDA protocol code points and data formats.

Reference: Pinal Dave (http://blog.sqlauthority.com)