多项选择题
A. backup pieces
B. copies of all the parameter files
C. trace file generated using BACKUP CONTROLFILE TO TRACE
D. control file autobackups
多项选择题 Lastnight，amediafailurecausedthelossofatemporaryfilethatbelongstoyourdatabase.Whichtwothingsmayhappenthismorningwhenyoutrytoopenyourdatabase？（）
多项选择题 WhataretheprerequisitesforenablingFlashbackDatabase？（）
单项选择题 TheDB_BLOCK_CHECKINGinitializationparameterissettoFALSE.Whatlevelofblockcheckingwouldbeperformed？（）