数据库实验（学生选课系统）

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数据库实验（学生选课系统）

2024-07-12 08:13| 来源: 网络整理| 查看: 265

数据库实验（学生选课系统）

文章目录数据库实验（学生选课系统）一、使用管理工具创建数据库二、使用T-SQL创建数据库三、SQL语句1.简单查询（一）2、简单查询（二）3.连接查询4.嵌套查询5.组合查询和统计查询四、代码：

一、使用管理工具创建数据库

1）使用 SQL Server Management Studio 建立学生选课数据库（XSXK）。

2）在 SQL Server Management Studio 中查看学生选课数据库的属性。

3）根据学生选课数据库物理结构设计，定义基本表、索引，实现相应的约束条件。

二、使用T-SQL创建数据库

（1） student(学生表)

字段名称数据类型长度大小允许空备注snochar10学号snamechar8姓名ssexchar2性别sagesmallint√年龄sdeptchar30√所在院系stelchar13√联系电话

主键：sno

索引：sname(升序)

check 约束：年龄大于 18, 性别的取值只能为男或女

default 约束：性别默认为男

更改学生表的结构，取消姓名不允许为空的约束

（2） Course （课程表）

字段名称数据类型长度大小允许空说明cnochar10课程编号cnamechar16课程名称ccreditsmallint学分cpnochar10√先行课

主键：cno

索引： cno (升序)+ccredit(降序)

更改课程表的结构，增加属性列教师 ctech（类型是 char ，长度 20）

（3） SC（选课表）

字段名称数据类型长度大小允许空备注snochar10学号cnochar10课程编号gradesmallint√成绩

主键：sno+cno

（4）各个表的参照完整性约束

FK_SC_ student

主键表：student 外键表：SC 主键：sno 外键：sno

FK_SC_ course

主键表：course 外键表：SC 主键：cno 外键：cno

3、SQL Server Management Studio 管理工具，完成图书借阅数据库的录入、数据修改或删除操作。

1）要求各表录入 10 条以上记录。

2）修改某位读者的还书日期。

3）删除指定读者的借还记录。

三、SQL语句 1.简单查询（一）

（1）对于每个学生，求学生的选课门数和平均成绩，并把结果存入学生选课数据库中。

（2）将数据库原理与应用课程的学分修改为 4.

（3）将姓名为“王华”的学生选修数据库原理及应用课程的成绩增加 5 分。

（4）删除选课表中成绩低于 40 分的记录。

（5）删除学号为 140001 的学生记录，并讨论该删除操作所受到的约束。

（6）删除所有选修课程“JAVA”的选课记录。

（7）将管理学院全体学生的成绩置为空。

（8）删除学生李萍的所有选课记录。

2、简单查询（二）

在学生选课数据库中实现其数据查询操作。

（1）查询数计学院学生的学号和姓名。

（2）查询选修了课程的学生学号。

（3）查询选修 C1 课程的学生学号和成绩,结果按成绩降序排列,如果成绩相同按学号升序排序。

（4）查询选修 C1 课程，成绩在 80~90 之间的学生学号和成绩,并将成绩乘以 0.8 输出。

（5）查询生工学院或数计学院系姓张的学生的信息。

（6）查询缺少了成绩的学生的学号和课程号。

3.连接查询

在学生选课库中实现其数据连接查询操作。

(1)查询学生的学号、姓名、选修的课程名称及成绩。

(2)查询数计学院学生选修的课程学分大于 2 的课程详细信息。

(3) 查询所有学生的信息以及他(她)所选课的学生学号和成绩（要求查询结果也显示出没有选修课程的学生信息）。

(4)查询选修课程号为 C1 且成绩在 90 分以上的学生学号、姓名及成绩。

(5) 查询每一门课的间接先行课（即先行课的先行课）。言的查询语句的理解。

4.嵌套查询

(1)查询选修了’c语言’课程的学生学号和姓名

(2)查询比唐伯虎年龄大的学生学号和姓名

(3)查询数据结构课程的成绩低于唐伯虎的学生学号和成绩

(4)查询其他学院中比数计学院学生年龄都小的学生

(5)查询选修了操作系统课程的学生姓名

(6)查询没有选修操作系统课程的学生姓名

(7)查询选修了全部课程的学生姓名

(8)查询至少选修了学生为张飞的学生所选修的全部课程的学生学号和姓名

(9)查询既选修了数据库原理又选修了操作系统课程的学生姓名

(10)查询既选修了数据库原理或选修了操作系统课程的学生学号

(11)查询既选修了数据库原理而没有选修操作系统课程的学生学号

(12)查询全是男同学选修的课程号

5.组合查询和统计查询

(1)使用集合运算查询既选修了数据结构课程又选修了数据库原理课程的学生姓名。 (2)使用集合运算查询选修了数据结构课程或选修了数据库原理课程的学生学号。

(3)使用集合运算查询选修了数据结构课程而没有选修了数据库原理课程的学生

(4)统计选修了课程的学生人数。

(5)查询选修成绩合格的课程超过4门以上学生的学生学号、总成绩。

(6)统计各院系的学生人数。

(7)统计各年龄的学生人数。

(8)统计每个学生的选修课程数目和平均成绩。

(9)查询每门课程的详细信息及选课人数。

四、代码： create table student ( sno char(10) not null comment '学号', sname char(8) not null comment '姓名', ssex char(2) default ' 男' not null check ( ssex = '男' or ssex = '女') comment '性别', sdept char(30) null comment '所在院系', sage smallint null check ( sage > 18 ) comment '年龄', stel char(13) null comment '联系电话', constraint student_pk primary key (sno) ) comment '学生'; create index student_sname_index on student (sname); create table Course ( cno char(10) not null comment '课程编号', cname char(16) not null comment '课程名称', ccredit smallint not null comment '学分', cpno char(10) null comment '先行课', constraint Course_pk primary key (cno) ) comment '课程表'; create index Course_cno_ccredit_index on Course (cno asc, ccredit desc); create table SC ( sno char(10) not null comment '学号', grade smallint null comment '成绩', cno char(10) not null comment '课程编号', constraint SC_pk primary key (sno, cno) ) comment '选课'; create index student_sname_index on student (sname); create table Course ( cno char(10) not null, cname char(16) not null, ccredit smallint not null, cpno char(10) null, constraint Course_pk primary key (cno) ); create index Course_cno_ccredit_index on Course (cno asc, ccredit desc); create table SC ( sno char(10) not null, grade smallint null, cno char(10) not null, constraint SC_pk primary key (sno, cno) ); alter table SC add constraint FK_SC_student foreign key (sno) references student (sno); alter table SC add constraint FK_SC_Course foreign key (cno) references Course (cno); insert into student values ('2001124001', '张飞', '男', '管理学院', 23, '1464312'); insert into student values ('2001124002', '郭旭', '男', '管理学院', 89, '1145114'); insert into student values ('2001124004', '周波', '男', '数计学院', 23, '4654654'); insert into student values ('2001124005', '张柏芝', '女', '数计学院', 30, '154666'); insert into student values ('2001124006', '风清扬', '男', '管理学院', 28, '14645463'); insert into student values ('2001124007', '唐伯虎', '男', '材料学院', 26, '1454643'); insert into student values ('2001124008', '于占鳌', '男', '电气学院', 25, '7842289'); insert into student values ('2001124009', '九儿', '女', '电气学院', 19, '774512'); insert into student values ('2001124010', '李茂贞', '女', '电气学院', 29, '6659873'); insert into student values ('2001124011', '紫霞', '女', '材料学院', 19, '4654562'); INSERT INTO Course VALUES ('001', 'java', '4', '003') , ('002', 'c语言', '4', '003') , ('003', '数据结构', '4', NULL) , ('004', '数据库原理', '3', '002') , ('005', '计算机组成原理', '2', NULL) , ('006', '操作系统', '2', '005') , ('007', '计算机网络原理', '3', NULL) , ('008', '高等数学', '5', NULL) , ('009', '大学英语一', '2', NULL) , ('010', '大学物理三', '3', NULL) ; insert into SC values ('2001124001', null, '001'), ('2001124001', 82, '002'), ('2001124001', 78, '003'), ('2001124001', 96, '004'), ('2001124001', 76, '005'), ('2001124001', 39, '006'), ('2001124001', 88, '007'), ('2001124001', null, '008'), ('2001124001', 82, '009'), ('2001124001', 69, '010'); insert into SC values ('2001124002', 98, '001'), ('2001124002', 92, '002'), ('2001124002', 78, '003'), ('2001124002', 96, '004'), ('2001124002', null, '005'), ('2001124002', 88, '006'), ('2001124002', 88, '007'), ('2001124002', 81, '008'), ('2001124002', 82, '009'), ('2001124002', 79, '010'); insert into SC values ('2001124005', 66, '001'), ('2001124005', 72, '002'), ('2001124005', 88, '003'), ('2001124005', 76, '004'), ('2001124005', 76, '005'), ('2001124005', 68, '006'), ('2001124005', 68, '007'), ('2001124005', 86, '008'), ('2001124005', 80, '009'), ('2001124005', null, '010'); insert into SC values ('2001124004', 46, '001'), ('2001124004', null, '002'), ('2001124004', null, '003'), ('2001124004', 87, '004'), ('2001124004', null, '005'), ('2001124004', 58, '006'), ('2001124004', 68, '007'), ('2001124004', 61, '008'), ('2001124004', 72, '009'), ('2001124004', 59, '010'); insert into SC values ('2001124006', 49, '001'), ('2001124006', 52, '002'), ('2001124006', 88, '003'), ('2001124006', 87, '004'), ('2001124006', 66, '005'), ('2001124006', 88, '006'), ('2001124006', 68, '007'), ('2001124006', 61, '008'), ('2001124006', 72, '009'), ('2001124006', null, '010'); insert into SC values ('2001124007', 86, '001'), ('2001124007', 42, '002'), ('2001124007', 69, '003'), ('2001124007', 87, '004'), ('2001124007', 65, '005'), ('2001124007', null, '006'), ('2001124007', 58, '007'), ('2001124007', 61, '008'), ('2001124007', 72, '009'), ('2001124007', 69, '010'); insert into SC values ('2001124008', 87, '001'), ('2001124008', 72, '002'), ('2001124008', 68, '003'), ('2001124008', 87, '004'), ('2001124008', 96, '005'), ('2001124008', 58, '006'), ('2001124008', 68, '007'), ('2001124008', 61, '008'), ('2001124008', 72, '009'), ('2001124008', 59, '010'); insert into SC values ('2001124009', 86, '001'), ('2001124009', 92, '002'), ('2001124009', 68, '003'), ('2001124009', 87, '004'), ('2001124009', 66, '005'), ('2001124009', 58, '006'), ('2001124009', 68, '007'), ('2001124009', 61, '008'), ('2001124009', 72, '009'), ('2001124009', 79, '010'); insert into SC values ('2001124010', 96, '001'), ('2001124010', null, '002'), ('2001124010', 88, '003'), ('2001124010', 87, '004'), ('2001124010', 86, '005'), ('2001124010', null, '006'), ('2001124010', null, '007'), ('2001124010', 79, '008'), ('2001124010', 72, '009'), ('2001124010', null, '010'); insert into SC values ('2001124011', 86, '001'), ('2001124011', 82, '002'), ('2001124011', 58, '003'), ('2001124011', 87, '004'), ('2001124011', 66, '005'), ('2001124011', 98, '006'), ('2001124011', 78, '007'), ('2001124011', 81, '008'), ('2001124011', null, '009'), ('2001124011', 79, '010'); alter table student add 平均成绩 double; alter table student add 选课门数 int; # 录入平均成绩 update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124001') where sno = '2001124001'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124002') where sno = '2001124002'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124004') where sno = '2001124004'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124005') where sno = '2001124005'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124006') where sno = '2001124006'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124007') where sno = '2001124007'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124008') where sno = '2001124008'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124009') where sno = '2001124009'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124010') where sno = '2001124010'; update student set 平均成绩=(select round(avg(grade), 1) from SC where sno = '2001124011') where sno = '2001124011'; # 查询一下所有的平均成绩可以对比一下是否录入正确 select SC.sno, AVG(grade) as 平均成绩 from SC group by SC.sno; # 录入选课门数 update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124001') where sno = '2001124001'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124002') where sno = '2001124002'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124004') where sno = '2001124004'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124005') where sno = '2001124005'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124006') where sno = '2001124006'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124007') where sno = '2001124007'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124008') where sno = '2001124008'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124009') where sno = '2001124009'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124010') where sno = '2001124010'; update student set 选课门数 = (select count(grade) from SC where SC.sno = '2001124011') where sno = '2001124011'; # 默认情况下null值不参与计算，所以不需要过滤 select count(grade) from SC where SC.sno = '2001124001'; # 修改'数据库原理'的学分为4 update course set ccredit=4 where cname = '数据库原理'; # 将姓名为唐伯虎的学生选修数据库原理课程的成绩加5 update sc set grade =grade + 5 where sno = (select student.sno from student where sname = '唐伯虎') and cno = (select cno from course where cname = '数据库原理'); # 删除选课表中成绩低于40分的记录 delete from sc where grade < 40; # 删除学号为2001124011的学生记录(删除单行数据) delete from sc where sno = 2001124011; # 删除所有选修java课程的选课记录 delete from sc where cno = (select cno from course where cname = 'java'); # 将管理学院全体学生成绩置为空 select sno from student where sdept = '管理学院'; #先查询是管理学院学生的学号 /*2001124001 2001124002 2001124006*/ update sc set grade=null where sno = 2001124001; update sc set grade=null where sno = 2001124002; update sc set grade=null where sno = 2001124006; # 删除学生郭旭的所有选课记录 delete from sc where sno = (select sno from student where sname = '郭旭'); # 实验二 # （一） # 1.查询数据学院学生的学号和姓名 select sno as 学号, sname as 姓名 from student where sdept = '数计学院'; # 2.查询选修了课程的学生学号 select sno as 学号 from student where student.选课门数 > 0; # 3.查询选修高等数学的课程的学生学号和成绩，结果按成绩降序排列，如果成绩相同按学号升序排列 select sno as 学号, grade as 成绩 from sc where cno = (select cno from course where cname = '高等数学') order by grade desc, sno asc; # 4.查询选修高等数学课程，成绩在80~90之间的学生学号和成绩，并将成绩乘以0.8输出 select sno as 学号, grade * 0.8 as 成绩 from sc where cno = (select cno from course where cname = '高等数学') and grade between 80 and 90; # 5.查询管理学院或数计学院姓张的学生的信息 select * from student where (sdept in ('管理学院', '数计学院')) and (sname like '张%'); # 6.查询少了成绩的学生的学号和课程号 select sno 学号, cno 课程号, grade from sc where grade is null; # （二） # 1.查询学生的学号，姓名，选修的课程名称及成绩 select distinct sc.sno 学号, student.sname 姓名, Course.cname 选修的课程, sc.grade 成绩 from sc left join student on sc.sno = student.sno left join course on sc.cno = Course.cno; # 2.查询数计学院学生选修的课程学分大于2的课程的详细信息 select distinct Course.* from sc left join student on sc.sno = student.sno left join course on sc.cno = Course.cno where student.sdept = '数计学院' and Course.ccredit > 2; # 3.查询所有学生信息以及他所选课的课程号和成绩 # (1) select distinct student.*, Course.*, sc.grade from sc left join student on sc.sno = student.sno left join course on sc.cno = Course.cno; # (2)要求查询结果也显示即使没有选课的学生的信息 select distinct student.*, Course.*, sc.grade from student left join sc on sc.sno = student.sno left join course on sc.cno = Course.cno; # 4.查询选修课课程号为002且成绩在90分以上的学生学号，姓名和成绩 select distinct sc.sno 学号, student.sname 姓名, sc.grade 成绩 from sc left join student on sc.sno = student.sno left join course on sc.cno = Course.cno where SC.cno = 002 and sc.grade > 90; # 5.查询每一门课的间接先行课 select c4.*, c5.cpno 间接先行课 from course c4 left join (select distinct c1.cno, c2.cpno from course c1, course c2, course c3 where c1.cpno = c2.cno and c2.cpno = c3.cno) c5 on c4.cno = c5.cno; # 实验三 # 1.嵌套查询 # (1)查询选修了'c语言'课程的学生学号和姓名 select sc.sno, (select sname from student where sno = sc.sno) 姓名 from sc where sc.cno = (select course.cno from course where cname = 'c语言'); # (2)查询比唐伯虎年龄大的学生学号和姓名 select s.sno 学号, s.sname 姓名 from student s where s.sage > (select sage from student where sname = '唐伯虎'); # (3)查询数据结构课程的成绩低于唐伯虎的学生学号和成绩 select * from student s where sno in (select SC.sno from sc where grade < (select grade from sc, student s, course c where sc.sno = s.sno and c.cno = sc.cno and s.sname = '唐伯虎' and c.cname = '数据结构')); # (4)查询其他学院中比数计学院学生年龄都小的学生 select * from student where sage < all (select sage from student where sdept = '数计学院'); # (5)查询选修了操作系统课程的学生姓名 select sname from student where sno in (select sno from sc where cno = (select cno from course where cname = '操作系统')); # (6)查询没有选修操作系统课程的学生姓名 select sname from student where sno not in (select sno from sc where cno = (select cno from course where cname = '操作系统')); # (7)查询选修了全部课程的学生姓名 select sname from student where sno in (select SC.sno from sc group by sno having count(*) = 10); # (8)查询至少选修了学生为张飞的学生所选修的全部课程的学生学号和姓名 select sno, sname from student where sno in (select distinct sno from SC c where not exists(select * from SC b where b.Sno = (select sno from student where sname = '张飞') and not exists(select * from SC a where a.Sno = c.Sno and a.Cno = b.Cno))); # (9)查询既选修了数据库原理又选修了操作系统课程的学生姓名 select sname from student where sno in (select a.sno from (select sno from sc where cno = (select cno from course where cname = '操作系统')) a inner join (select sno from sc where cno = (select cno from course where cname = '数据库原理')) b on a.sno = b.sno); # (10)查询既选修了数据库原理或选修了操作系统课程的学生学号 select sno from sc where cno = (select cno from course where cname = '操作系统') union select sno from sc where cno = (select cno from course where cname = '数据库原理'); # (11)查询既选修了数据库原理而没有选修操作系统课程的学生学号 select sno from student where sno in (select a.sno from (select sno from sc where cno = (select cno from course where cname = '数据库原理')) a left join (select distinct sno from sc where cno = (select cno from course where cname = '操作系统')) b on a.sno = b.sno where b.sno is null); # (12)查询全是男同学选修的课程号 select distinct cno from SC x where not exists(select cno from student where ssex = '女' and exists(select * from SC y where y.cno = x.cno and y.sno = student.sno)); # 2.组合查询和统计查询 #(1)使用集合运算查询既选修了数据结构课程又选修了数据库原理课程的学生姓名。 # mysql8.0不支持intersect select s.sname from student s where s.sno in (select t1.sno from (select sno from SC where cno = (select cno from Course where cname = '数据结构')) t1 inner join (select sno from SC where cno = (select cno from Course where cname = '数据库原理')) t2 on t1.sno = t2.sno); #(2)使用集合运算查询选修了数据结构课程或选修了数据库原理课程的学生学号。 select sname from student where sno in (select sno from SC where cno in (select cno from Course where cname = '数据结构')) union select sname from student where sno in (select sno from SC where cno in (select cno from Course where cname = '数据库原理')); #(3)使用集合运算查询选修了数据结构课程而没有选修了数据库原理课程的学生 # mysql8.0不支持except select sname from student where sno in (select sno from SC sc1 where sc1.cno in (select cno from Course where cname = '数据结构')) and sno not in (select sc2.sno from SC sc2 where sc2.cno in (select cno from Course where cname = '数据库原理')); #(4)统计选修了课程的学生人数。 select count(distinct sno) as stusum from SC; #(5)查询选修成绩合格的课程超过4门以上学生的学生学号、总成绩。 select sc.sno, sum(sc.grade) gradesum from sc where sc.grade >= 60 group by sc.sno having count(sc.cno) >= 4; #(6)统计各院系的学生人数。 select s.sdept, count(s.sdept) sum from student s group by s.sdept; #(7)统计各年龄的学生人数。 select s.sage, count(s.sage) sum from student s group by s.sage; #(8)统计每个学生的选修课程数目和平均成绩。 select sno, count(sc.sno) stusum, avg(sc.grade) avggrade from sc group by sno; #(9)查询每门课程的详细信息及选课人数。 select Course.*, 选课人数 from Course left join (select cno, count(*) 选课人数 from SC group by cno) as a on a.cno = Course.cno;

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数据库实验（学生选课系统）

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