有学生表student,包含的属性有学号sno、学生姓名sname、性别sex、年龄age、所在专业smajor。基于student表建立如下视图,其中可以进行数据更新的是

1. A. CREATE VIEW V1 AS SELECT sno,sname FROM student;
2. B. CREATE VIEW V2(major) AS SELECT DISTINCT(smajor) FROM student;
3. C. CREATE VIEW V3(major,scount) AS SELECT smajor,COUNT(*) FROM student GROUP BY smajor;
4. D. CREATE VIEW V4(sname,sage) AS SELECT sname,age+5 FROM student where sno='101';