20151013视图

--视图
create view shitu
as
select Score.sno,Score.degree,sname,ssex,sbirthday,class,Course.cno,Course.cname,Teacher.tno,tname
From Score join Student on Score.sno= Student.sno
join Course on Score.cno =Course.cno
join Teacher on Teacher.tno=Course.tno
go
select *from shitu

--范式理论
1.每一个表都要有主键
2、每一个表的列都要直接跟主键相关
3.每一列都要试单独的数据列