单项选择题
A.show user;B.select *from all_users;C.select user from users;D.show users;
A.打开数据库、启动例程、装载数据库B.启动例程、装载数据库、打开数据库C.启动例程、打开数据库、装载数据库D.装载数据库、启动例程、打开数据库
A.ALTER DATABASE ARCHIVELOG;B.ALTER DATABASE BEGIN BACKUP;C.ALTER DATABASE END BACKUP;D.ALTER SYSTEM ARCHIVE LOG CURRENT;