单项选择题
A.执行以下命令重建redo组:alter database clear logfile group 1B.删除对应的redo组,然后重建C.恢复数据库到故障前D.切换redo组
A.DBA_DIRECTORIESB.USER_DIRECTORIESC.USER_DIRECTORIED.DBA_DIRECTORIE
A.smonB.lgwrC.dbwrD.mmon