modify 数据库.doc
Merge branch 'master' of https://github.com/rankun203/OnlineTeach.git
Merge branch 'master' of https://github.com/rankun203/OnlineTeach.git
Merge branch 'master' of https://github.com/rankun203/OnlineTeach.git
Merge branch 'master' of https://github.com/rankun203/OnlineTeach
更改数据库模型
modify cdm