单项选择题
A.系统管理员 B.流复制用户 C.数据库拥有者 D.一般用户
A.DML B.DQL C.DCL D.DDL
A.REVOKE CONNECT ON DATABASE dbname FROM USERS; B.REVOKE CONNECT ON DATABASE dbname FROM SUPERUSERS; C.REVOKE CONNECT ON DATABASE dbname FROM ALL USERS; D.REVOKE CONNECT ON DATABASE dbname FROM PUBLIC;