经过调查分析，该系统的使用者大概可以分三类：学生，教师，教学秘书。他们有各自的使用权限，可在权限范围内对后台数据库数据进行维护，包括数据的修改、删除、输入等等。-After investigation, analysis, perhaps the user of the system can be divided into three categories: students, teachers, teaching secretary. They have their own permissio