写出如下SQL实现语句。(1)把对表Zone的INSERT权限授予用户Smith,并允许它再将此权限授予他人。(2)

Question

写出如下SQL实现语句。

(1)把对表Zone的INSERT权限授予用户Smith，并允许它再将此权限授予他人。

(2)收回已经授予Tom的对表FlowerInfo中属性ComName的修改权限。

(3)建立视图viewpot，表现问题2的功能。

Answer 1

正确答案：(1) GREANT INSERT ON TABLE Zone TO Smith WITH GRANT OPTION (2) REVOKE UPDATE(ComName)ON TABLE FlowerInfo FROM Tom (3) CREATE VIEW Viewpot(IDComName DeISize) AS SELECT FlowerInfo.IDFlowerInfo.ComNameDelivery.DelSize
(1) GREANT INSERT ON TABLE Zone TO Smith WITH GRANT OPTION (2) REVOKE UPDATE(ComName)ON TABLE FlowerInfo FROM Tom (3) CREATE VIEW Viewpot(ID,ComName, DeISize) AS SELECT FlowerInfo.ID,FlowerInfo.ComName,Delivery.DelSize 解析：SQL语言中的数据控制语句有授权(GRANT)和收获权限(REVOKE)，其基本格式分别如下：
GRANT权限＞[,权限＞]…
[ON对象类型＞对象名＞]
TO用户＞[,用户＞]…
[WHERE GRANT OPTION]
REVOKE权限＞[,权限＞]…
[ON对象类型＞对象名＞]
FROM用户＞[,用户＞]…
据此可得问题(1)对应的SQL语句为GREANT INSERT ON TABLE Zone TO Smith WITH GRANT OPTION；问题(2)对应的SQL语句为REVOKE UPDATE(ComName)ON TABLE FlowerInfO FROM Tom。
问题(3)是创建视图，用CREATE VIEW语句实现，其基本格式为：
CREATE VIEW 视图名(列表名)
AS SELECT 查询子句
[WITH CHECK OPTION]
根据题意可得对应的SQL语句为：
CREATE VIEW Viewpot(ID,ComName,DelSize)
AS
SELECT FlowerInfo.ID,FlowerInfo.ComName,Delively.DelSize
FROM FlowerInfo AS F,Delivery AS D
WHERE F.Delivered=D.id AND D.Category='pot'
ORDER BY F.ComName DESC