题目内容
（请给出正确答案）
A、CREATE VIEW S_AVG(学号,平均分) AS SELECT 学号,AVG(分数) FROM score WHERE 分数IS NOT NULL GROUP BY 学号;
B、CREATE VIEW S_FEMALE(姓名,出生日期) AS SELECT 姓名,出生日期 FROM student WHERE 性别='女';
C、CREATE VIEW S_MALE(学号,姓名) AS SELECT 学号,姓名 FROM student WHERE 班号='09031';
D、CREATE VIEW S_G(学号,姓名,课程名,分数) AS SELECT S.学号,姓名,课程名,分数 FROM S, SC, C WHERE S.学号=SC. 学号AND SC. 课程号 = C. 课程号;
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更多“以下定义的4个视图中，能够进行更新操作的是（）。”相关的问题
A.查询
B.在视图上定义新的视图
C.更新视图
D.在视图上定义新的表
A更新视图数据
B查询
C在视图上定义新的基本表
D在视图上定义新视图
A．视图与数据库表相同，用来存储记录
B．视图不能同数据库表进行连接操作
C．在视图上不能进行更新操作
D．视图是从一个或多个数据库表导出的虚拟表
A、从用户视图使用System-view命令可以切换到系统视图
B、从系统视图使用相关的业务命令可以进入其他业务视图
C、从系统视图使用exit命令可以切换到用户视图
D、不同的视图下可以使用的命令也不同
A、create view view1 as select sno, avg(grade) from sc group by sno
B、create view view2 as select sno, sname, sdept from student where sdept='CS'
C、create view view3 as select sno, sage+20 from student where ssex='女'
D、create view view4 as select student.sno, sname, sc.sno, cno, grade from sc,student where sc.sno=student.sno and cno='1'
B．视图的存在提高了系统的并发度
C．视图与基本表的最大区别在于它是逻辑定义的虚表
D．视图简化了用户观点,对所有的视图都可以进行更新操作
A、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 GROUP BY S# HAVING COUNT(*)>=4 ORDER BY Sgrade DESC;
B、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 and COUNT(*)>=4 GROUP BY S# ORDER BY Sgrade DESC;
C、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 GROUP BY S# HAVING COUNT(*)>=4 ORDER BY Sgrade;
D、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 HAVING COUNT(*)>=4 GROUP BY S# ORDER BY Sgrade DESC;
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