《数据库系统概论》课程学习(21)——建立学生课程数据库SQL

create database MYDB
on (name = mydbdata, filename = 'e:\MyDB\MyDB.mdf ')
log on (name = mydblog, filename = 'e:\MyDB\MyDBlog.ldf ')

use mydb

create table Student
( Sno   char(9)   primary key,
  Sname char(20)  unique,
  Ssex  char(2),
  Sage  smallint,
  Sdept char(20) )

create table Course
( Cno    char(4)  primary key,
  Cname  char(20) not null,
  Cpno   char(4),
  Credit smallint,
  foreign key(Cpno) references Course(Cno))

create table SC
( Sno   char(9),
  Cno   char(4),
  Grade smallint,
  primary key(Sno,Cno),
  foreign key(Sno) references Student(Sno),
  foreign key(Cno) references Course(Cno))

insert into student values('1','李勇','男',20,'CS')
insert into student values('2','刘晨','女',19,'CS')
insert into student values('3','王敏','女',18,'MA')
insert into student values('4','张立','男',19,'IS')

insert into Course values('1','数据库',null,4)
insert into Course values('2','数学',null,2)
insert into Course values('3','信息系统',null,4)
insert into Course values('4','操作系统',null,3)
insert into Course values('5','数据结构',null,4)
insert into Course values('6','数据处理',null,2)
insert into Course values('7','C语言',null,4)

update Course set cpno = '5' where cno = '1'
update Course set cpno = '1' where cno = '3'
update Course set cpno = '6' where cno = '4'
update Course set cpno = '7' where cno = '5'
update Course set cpno = '6' where cno = '7'

insert into sc values('1','1',92)
insert into sc values('1','2',85)
insert into sc values('1','3',88)
insert into sc values('2','2',90)
insert into sc values('2','3',80)