http://blog.csdn.net/no_mIss/archive/2006/11/09/1374978.aspx
http://www.itgrass.com/a/db/SQL-Server/200806/20-18648.html
http://www.oracle.com.cn/viewthread.php?tid=80153
http://www.cnblogs.com/lovewindy/archive/2005/02/19/105959.html
http://www.cnblogs.com/winner0203/articles/891785.html