单项选择题 You have discovered that a disk failure occurred on DISK1 where the data files belonging to the SYSTEM and USER_DATA tablespaces is stored. The database is currently open and you need to recover the data files. You will restore the data files to DISK2. What is the correct sequence of RMAN commands to restore and recover the data files？（）

单项选择题 Aftertherecoveryiscomplete，whichcommandshouldyouexecute？（）

单项选择题 Whileconnectedtothedatabase，auseronaPCreceivesafatalerrorandthemachinereboots.Whichbackgroundprocesscleansupthefailedconnection？（）