创建视图
create view IS_Student(sno,sname,grade)
as
select student.sno,sname,grade
from student,sc
where student.sno = sc.sno
and sdept = 'IS'
and cno = '2'
with check option
删除视图
drop view IS_student
视图之间的相互索引
create view IS_s1(sname,grade)
as
select sno,grade
from IS_student
where grade > 90