数据库第一次记录

最新推荐文章于 2024-03-06 23:38:07 发布

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最新推荐文章于 2024-03-06 23:38:07 发布

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本文详细介绍了如何使用SQL语言进行数据库操作，包括数据定义、数据插入、更新及删除等基本操作，并展示了具体的SQL语句实例。

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（一）数据定义
一：
1.1
create table student
(sno varchar(9) primary key,
sname varchar(20),
ssex varchar(2),
sage int,
sdept varchar(20));

1.2
create table Course
(cno varchar(4) primary key,
cname varchar(40) not null ,
cpno varchar(4),
ccredit smallint,
foreign key(cpno) references Course (cno)
);

1.3
create table SC
( Sno varchar(9),
Cno varchar(4),
Grade int,
primary key(Sno,Cno),
foreign key(Sno)references Student(Sno),
foreign key(Cno)references Course(Cno)
);

2.1
alter table student add bloodtype char(2);

2.2
alter table student modify sdept varchar2(40);

2.3
alter table student add constraint student_sage_chk check (sage between 16 and 29);

2.4
alter table student drop constraint student_sage_chk;

2.5
alter table student drop column bloodtype ;

3.1
Drop Table Student Cascade Constraints;

3.2
Drop Table Sc Cascade Constraints;

二：
1.1
CREATE UNIQUE INDEX stusnam_4068 ON student(Sname);
1.2
CREATE UNIQUE INDEX sc_4068 ON SC(Sno ASC,Cno DESC);

2.1
drop index stusnam_4068;
2.2
drop index sc_4068;
（二）数据操作
一：
1.1
insert into Student values('200215121','李勇','男',20,'CS');
insert into Student values('200215122','刘晨','女',19,'CS');
insert into Student values('200215123','王敏','女',18,'MA');
insert into Student values('200215125','张立','男',19,'IS');
1.2
insert into COURSE values('6','数据处理',null,2);
insert into COURSE values('2','数学',null,2);
insert into COURSE values('4','操作系统','6',3);
insert into COURSE values('7','PASCAL语言','6',4);
insert into COURSE values('5','数据结构','7',4);
insert into COURSE values('1','数据库','5',4);
insert into COURSE values('3','信息系统','1',4);
1.3
insert into SC values('200215121','1',92);
insert into SC values('200215121','2',85);
insert into SC values('200215121','3',88);
insert into SC values('200215122','4',90);
insert into SC values('200215122','3',80);

2.1
update Student set Sage=20 where sname='王敏';
2.2
update Student set Sage=Sage+1;
2.3
update sc
set grade=0
where sno in
(select sno from STUDENT where sdept='CS');
3.1
delete from student where sdept=
(select sdept from Student where sname='刘晨');
3.2
先添加cs两条记录
delete from sc where sno in
(select sno from student where sdept='CS');