Your database is running in ARCHIVELOG mode. One of the data files， USERDATA01.dbf， in the USERS tablespace is damaged and you need to recover the file until the point of failure. The backup for the datafile is available. 
Which three files would be used in the user-managed recovery process performed by the database administrator （DBA）？（） 

单项选择题You work with a newly created database. Presently， there is no application load on the database instance. You want to create a baseline for tuning the application， so you decide to collect recommendations that can be implemented to improve application performance.  What action must you take to achieve this？（）

A. Run Segment Advisor
B. Run the SQL Tuning Advisor （STA）
C. Run the Automatic Workload Repository （AWR） report
D. Run the SQL Access Advisor with a hypothetical workload

单项选择题Youneedtomaintainarecordofalltransactionsonsometablesforatleastthreeyears.Automaticundomanagementisenabledforthedatabase.Whatmustyoudoaccomplishthistask？（）

A. Enable supplemental logging for the database.
B. Specify undo retention guarantee for the database
C. Create Flashback Data Archive in the tablespace where the tables are stored.
D. Create Flashback Data Archive and enable Flashback Data Archive for specific tables

多项选择题YouhaveenabledbackupoptimizationfortheRMANenvironment.IdentifytwocriteriaonwhichRMANwillskipthefile，ifithasalreadybeenbackedup.（）

A. The data file backup is done with multiple channels
B. The data files is in the read-write mode after being backed up in the read only mode
C. The backup was taken after the data files was taken offline-normal or is in the read only mode
D. The data file backup complies with the back retention policy and the backup duplexing fe ture

单项选择题You want to set the following initialization parameters for your database instance：   LOG_ARCHIVE_DEST_1 = ’LOCATION= disk1 arch’ LOG_ARCHIVE_DEST_2 = ’LOCATION= disk2 arch’ LOG_ARCHIVE_DEST_3 = ’LOACTION= disk3 arch’ LOG_ARCHIVE_DEST_4 = ’LOCATION= disk4 arch MANDATORY’   Identify the statement that correctly describes this setting.（）

A. The MANDATORY location must be a flash recovery area.
B. The optional destinations may not use the flash recovery area.
C. This setting is not allowed because the first destination is not set as MANDATORY.
D. The online redo log file is not allowed to be overwritten if the archived log cannot be created in the fourth destination.

单项选择题Before a Flashback Table operation，you execute the following command：   ALTER TABLE employees ENABLE ROW MOVEMENT；   Why would you need this to be executed？（）

A. Because row IDs may change during the flashback operation
B. Because the object number changes after the flashback operation
C. Because the rows are retrieved from the recycle bin during the flashback operation
D. Because the table is moved forward and back to a temporary during the flashback opertion