单项选择题
A.grant delete on students to helloB.revoke delete on students to helloC.revoke delete on students from helloD.deny delete on students to hello
A.每个角色有一定的权限B.是服务器权限的集合C.不能创建服务器角色D.能创建服务器角色
A.CREATE USER user_name FOR LOGIN login_nameB.ALTER USER username WITH NAME=newusernameC.create login name with password=’abcd1234@’D.CREATE ROLE role_name AUTHORIZATION owner_name