第三方的SQL Server and Sybase的Jdbc dirver,速度更快，支持回滾（ms 原版不支持）。
Open source Jdbc 3.0 Type 4 driver for Microsoft SQL Server (6.5, 7.0, 2000 and 2005) and Sybase. jTDS is the fastest Jdbc driver for MS SQL Server and is a complete implementation of the Jdbc spec.
