上机实验三:
(一)四个基本表的定义
1. Create Table Student
(
Sno Char(7) primary key,
Sname varchar(20) not null,
Ssex char(2) not n
ull,Sage smallint,
Clno char(5) not null
)
2. Create Table Course
(
Cno char(1) not null unique,
Cname varchar(20) not null,
Credit smallint
)
3. Create Table class
(
Clno char(5) not null unique,
Speciality varchar(20) not null,
Inyear char(4) not null,
Number int ,
Monitor char(7)
)
4. create Table Grade
(
Sno char(7) not null,
Cno Char(1) not null,
Gmark Numeric(4,1)
)
(二)T11
1. alter table Student add Nation Varchar(20);
2. alter table Student drop column Nation;
3. insert into Grade values('2001110','3',80);
4. update Grade set Gmark=70 where Sno='2001110';
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