请高手完善下：“学生信息查询（增删改查）”,"教务信息维护（维护学生、系、课程和学生选课及成绩）"...

代码说明：

请高手完善下：“学生信息查询（增删改查）”,"教务信息维护（维护学生、系、课程和学生选课及成绩）"----教务员使用（口令）。“学生选课（选课、退选）”----学生使用（口令）。完成请你吃饭啊！-Please complete the next master: " Student Information Query (additions and deletions to change search)" , " Academic Information Maintenance (maintenance students, department, course and student elective and achievement )"---- Senate members to use (password). " Students elective (elective, withdrawal of candidature )"---- students to use (password). The completion of treat you to dinner ah!