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.
