编辑代码

create database xuesheng;
use xuesheng;
create table student
(
    sno char(7) primary key,
    sname varchar(16),
    ssex char(2) default '男',
    sage smallint,
    sdept char(2)
);
create table course
(
    cno char(2) not null,
    cname varchar(20),
    cpno char(2),
    ccredit smallint,
    primary key(cno),
    foreign key(cpno) references course(cno)
);
create table sc
(
    sno char(7) not null,
    cno char(2) not null,
    grade smallint,
    primary key(sno,cno),
    foreign key(sno) references student(sno),
    foreign key(cno) references course(cno)
);
insert into student values
('2005001','钱横','男',18,'CS'),
('2005002','王林','女',19,'CS'),
('2005003','李民','男',20,'IS'),
('2005004','赵欣然','女',16,'NA');
select * from student;
-- insert into course values
-- ('1','数据库系统',5,4)
-- ('2','数学分析',NULL,2)
-- ('3','信息系统导论',1,3)
-- ('4','操作系统原理',6,3)
-- ('5','数据结构',7,4)
-- ('6','数据处理基础',null,4)
-- ('7','C语言',6,3);

-- ('2','数学分析',NULL,2)
-- ('6','数据处理基础',null,4);
--insert into sc values
--('2005001','1',87)
--('2005001','2',67)
--('2005001','3',90)
--('2005002','2',95)
--('2005003','3',88);