文件和文件组

http://www.cnblogs.com/kissdodog/p/3155016.html

http://www.cnblogs.com/CareySon/archive/2011/12/26/2301597.html

http://www.cnblogs.com/xinysu/p/6949867.html

https://technet.microsoft.com/en-us/library/ms179316(v=sql.105).aspx