数据库资料

http://www.docin.com/p-176895291.html 

http://www.cnblogs.com/zhixx/archive/2012/02/21/2360833.html 

http://www.umlchina.com/xprogrammer/issue/15/RelOO.htm 

http://blog.csdn.net/zhiyang202/article/details/448381