1、数据库第二次作业数据库第二次作业上机实验题实验一:交互式SQL的使用实验要求:1,创建Student数据库,包括Students,Courses,SC表,表结构如下:Students(SNO,SNAME,SEX,BDATE,HEIGHT,DEPARTMENT)Courses(CNO,CNAME,LHOUR,CREDIT,SEMESTER)SC(SNO,CNO,GRADE)(注:下划线表示主键,斜体表示外键),并插入一定数据。答:create table Students(SNO varchar(100) primary key,SNAME varchar(100) null,SEX varch
2、ar(100) null,BDATE datetime null,HEIGHT decimal null,DEPARTMENT varchar(100) null)gocreate table Courses(CNO varchar(100) primary key,CNAME varchar(100) null,LHOUR int null,CREDIT int null,SEMESTER varchar(100) null)goCREATE TABLE dbo.SC( SNO varchar(100) NOT NULL, CNO varchar(100) NOT NULL, GRADE i
3、nt NULL, CONSTRAINT PK_SC PRIMARY KEY CLUSTERED( SNO ASC, CNO ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON PRIMARY) ON PRIMARYGOALTER TABLE dbo.SC WITH CHECK ADD CONSTRAINT FK_SC_CoursesFOREIGN KEY(CNO)REFERENCES dbo.Cours
4、es(CNO)GOALTER TABLE dbo.SC CHECK CONSTRAINT FK_SC_CoursesGOALTER TABLE dbo.SC WITH CHECK ADD CONSTRAINT FK_SC_StudentsFOREIGN KEY(SNO)REFERENCES dbo.Students (SNO)GO ALTER TABLE dbo.SC CHECK CONSTRAINT FK_SC_Students2完成如下的查询要求及更新的要求。(1)查询身高大于的男生的学号和姓名;答:select SNO,SNAME from Students where HEIGHT(2
5、)查询计算机系秋季所开课程的课程号和学分数;(3)答:(4)select CNO,CREDIT from Courses where SEMESTER=秋季(5)查询选修计算机系秋季所开课程的男生的姓名、课程号、学分数、成绩;(6)答:(7)select , from students s(8)inner join SC on =(9)inner jpin Courses c on =c,CNO(10)where =计算机系and =男and =秋季(11)查询至少选修一门电机系课程的女生的姓名(假设电机系课程的课程号以EE开头);(12)答:(13)select distinct from
6、Students s,sc where = and =女and like EE%(14)查询每位学生已选修课程的门数和总平均成绩;(15)答:(16)select count as 课程门数,avg as 总平均成绩from students s(17)inner join SC on =(18)inner join Courses c on =(19)groupby(6)查询每门课程选课的学生人数,最高成绩,最低成绩和平均成绩;答:selectcname,count(cno),max(grade),min(grade),avg(grade)fromstudentsnaturaljoinscn
7、aturaljoincoursesgroupbychane;(7)查询所有课程的成绩都在80分以上的学生的姓名、学号、且按学号升序排列;答:selectsname,snofromstudentsnaturaljoin(select(grade)as mini fromscgroupbysno)wheremini80orderby(sno);(8)查询缺成绩的学生的姓名,缺成绩的课程号及其学分数;答:select sname,creditfrom students,courses,scwhere = and = and grade is null;(9)查询有一门以上(含一门)三个学分以上课程的
8、成绩低于70分的学生的姓名;(10)答:(11)select sname from students,courses,sc(12)where = and = and credit=3 and grade70;(10)查询1984年1986年出生的学生的姓名,总平均成绩及已修学分数。答:select sname,avg(grade),sum(credit)from students natural join sc natural join courseswhere bdate between 1984-00-00and 1987-00-00groud by sname(11) 在STUDENT和
9、SC关系中,删去SNO以01开关的所有记录。答:delete sc where SNO like %01%delete Students where SNO like %01%(12)在关系中增加以下记录:答:insert into students values insert into students values (13)将课程CS-221的学分数增为,讲课时数增为(14)答:(15)update courses set credit=3 where cno=CS-211(16)update courses set 1hour=60 where cno=CS-2113补充题:(1) 统计
10、各系的男生和女生的人数。答:select department,sum(case wgen sex=男then 1 else 0 end),sum(case wgen sex=女then 1 else 0 end),count(sno) from students group by department order by deparment;(2) 列出学习过编译原理,数据库或体系结构课程,且这些课程的成绩之一在90分以上的学生的名字。答:select snmefrom students natural join sc natural join courseswhere cname=编辑原理o
11、r cname=体系结构 and grade90(3) 列出未修选电子技术课程,但选修了数字电路或数字逻辑课程的学生数。答:select count(distinci from courses, not in (select from = and cname=电子技术)and in (select cno from courses where cname=数学逻辑or cname=数字电路)(4) 按课程排序列出所有学生的成绩,尚无学生选修的课程,也需要列出,相关的学生成绩用NULL表示。答:select distinct ,sno,grade from courses left join s
12、c on group by ,sno,gradegroup by ,sno,grade;(5) 列出平均成绩最高的学生名字和成绩。(SELECT句中不得使用TOP n子句)答:select sname,rfrom(select sname,avg(grade)as from students,sc where = group by sname, order by r desc)where rownum=1;4选做题:对每门课增加“先修课程”的属性,用来表示某一门课程的先修课程,每门课程应可记录多于一门的先修课程。要求:1) 修改表结构的定义,应尽量避免数据冗余,建立必要的主键,外键。2) 设计
13、并插入必要的测试数据,完成以下查询:列出有资格选修数据库课程的所有学生。(该学生已经选修过数据库课程的所有先修课,并达到合格成绩。)注意:须设计每个查询的测试数据,并在查询之前用INSERT语句插入表中。实验二:数据库的安全和完整性约束实验要求:1采用实验一的建库脚本和数据插入脚本创建Student数据库,并完成以下操作:1)新增表Credits(SNO,SumCredit,NoPass),表示每学生已通过选修课程的合计学分数,以及不及格的课程数。答:create table Credits(SNO varchar(100),SumCredit int,NoPass int)2)创建视图Stu
14、dent_Grade(Sname,Cname,Grade),表示学生选修课程及成绩的详细信息。答:create view Student_Gradeasselect , from students sinner join SC on =inner join Courses c on =2. 在数据库中创建以下触发器:1) Upd_Credit要求:当在SC表中插入一条选课成绩,自动触发Upd_Credit,完成在Credits表中修改该学生的合计学分数和不及格的课程数。答:create trigger Upd_Credit on SC for insertasdeclare SNO varch
15、ar(100),CNO varchar(100),GRADE int,NoPass int,CREDIT intselect SNO=SNO,CNO=CNO,GRADE=GRADE,NoPass=(case when GRADE3group by 4) CAL_GPA (SNO,GPA output)要求:根据SNO参数, 输出并显示该学生的GPA值。计算方法如下:GRADE(G) GRADEPOINT(GP)G=85 485G=75 375G=60 260G 1GPA= (GP*CREDIT)/ CREDIT)答:create procedure CAL_GPASNO varchar(100
16、),GPA decimal outputasdeclare SUM_CREDIT int,AVG_GRADE int,ALL_CREDIT intselect SUM_CREDIT=SumCredit from Creditswhere SNO=SNOselect AVG_GRADE=avg(case when =85 then 4 when 85 and =75 then 3 when 75 and =60 then 2 when 60 then 1 end) from Students sinner join SC on =where =SNO and 3group by select G
17、PA=(AVG_GRADE*SUM_CREDIT)/ALL_CREDIT3选做题: 使用其它程序设计语言编程,连接数据库并提交SQL语句,显示查询结果。 要求:实现上题中的第3)小题要求,设计一个图形界面来输入查询的参数SNO,及显示查询的结果。(如采用VC+,VB等)实验四:事务的管理(选作)实验要求:1 采用实验一的建库脚本和数据插入脚本创建Student数据库。2 测试事务隔离级别,要求: 分别设置不同的隔离级别,包括:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;SET TRANSACTION ISOLATION LEVEL READ COMMITTED;SET TRANSACTION ISOLATION LEVEL READ ONLY;两个并发事务交错执行的程序,能分别显示每种隔离级别下,是否出现丢失更新,脏读,读值不可复现以及幻象四种情况。3备份与恢复 备份数据库 答: BACKUP DATABASE test TO disk = c:test 删除sc表 答: DROP TABLE SC 恢复到删除之前 答: USE master GO RESTORE DATABASE test_wt FROM disk = c:test_wt GO
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