create database StuInfo
create table Course(
Cno char(10) ,Cname char(30),Ccredit real
)
create table Score ([Cno] [nchar](10) NULL,
[Sno] [char](10) NULL,
[Grade] [real] NULL)
CREATE TABLE Student(
[Sno] [char](10) NOT NULL,
[Sname] [nchar](10) NULL,
[Sex] [char](10) NULL,
[Birthday] [datetime] NULL,
[Sdept] [nchar](10) NULL,
[memo] [varchar](200) NULL)
insert into Student values('008','过放电','男','2012-5-2','如见','')
alter table Student add memo varchar(200)
alter table Student drop column memo
alter table Score alter column Sno char(10)
alter table Student alter column Sno char(10) not null
alter table Student add primary key(Sno)
alter table Student alter column memo varchar(300)
alter table Score ADD FOREIGN KEY(Sno) REFERENCES Student (Sno)
delete from Student where Sno='008'
alter table Score add constraint fk_sc1 foreign key(Sno) references Student(Sno)