此文档用Oracle实现了高校网上选课系统，高校选课系统将包含学生、教师、管理员等实体，学生可以在规定的时间内选课、退选和成绩查询等操作；教师可以查看学生的相关信息，录入学生成绩等操作；管理员可以添加管理员，管理教师、学生等信息-This document is realized with Oracle online course selection system universities, university enrollment system will include students, teachers, administrators and other entities, students elective within the stipulated time, withdrawal and query results and other operations　Teachers can view student information, Input student achievement and other operations　administrator can add administrators manage teachers, students and other information