单项选择题 Which are the correct steps， in order， to deal with the loss of an online redo log if the database has not yet crashed？（）   a. Issue a checkpoint.  b. Shut down the database.  c. Issue an alter database open command to open the database.  d. Startup mount the database.  e. Issue an alter database clear logfile command.  f. Recover all database datafiles.

多项选择题 WhichfileswillyouneedtoperformafullrecoveryofadatabasebackedupinNOARCHIVELOGmode？（）

单项选择题 You have discovered that one of three control files has been lost. What steps would you follow to recover that control file？（）   a. Shut down the database.  b. Restore a control-file copy from backup media.  c. Use the create control file command to create a new control file.  d. Copy the backup control file into place.  e. Create a new copy of the control file from one of the surviving control files.  f. Recover the database using the recover database using backup control file command.  g. Start up the database.