You want to use RMAN to create compressed backups.Which statement is true about the compression algorithms that RMAN can use?（）

单项选择题You have the following requirements in relation to the detection of block corruption for your database instance: 1. Check for logical self-consistency of data blocks when modified in memory. 2. Checksums are calculated before and after the block change. 3. Checks are performed for the lost writes to the physical standby database. Which method would help you perform the above checks automatically? （）

A. Set the DB_SECUREFILE parameter to PERMITTED
B. Set the DB_ULTRA_SAFE parameter to DATA_ONLY
C. Set the DB_LOCK_CHECKSUM parameter to TYPICAL
D. Set the DB_LOST_WRITE_PROTECT parameter to TYPICAL

单项选择题To control the execution of a server process when it is receiving bad packets from a potentially malicious client, you set the SEC_PROTOCOL_ERROR_FURTHER_ACTION initialization parameter as follows: SQL> ALTER SYSTEM SET SEC_PROTOCOL_ERROR_FURTHER_ACTION = Drop,10; What is the significance of this setting?（）

A. It terminates the client connection after 10 bad packets and the client cannot reconnect to the same instance.
B. It terminates the client connection after 10 bad packets but the client can still reconnect, and attempt the same operation again.
C. It terminates the client connection 10 seconds after receiving a bad packet and the client cannot reconnect to the same instance.
D. It terminates the client connection after receiving a bad packet and the client can reconnect to the same instance after 10 minutes.

单项选择题Examine the following command: ALTER DISKGROUP data MOUNT FORCE; In which scenario can you use the above command to mount the disk group? （）

A. when ASM disk goes offline
B. when one or more ASM files are dropped
C. when some disks in a disk group are offline
D. when some disks in a failure group for a disk group are rebalancing

单项选择题Which statement about recovering from the loss of a redo log group is true?（）

A. If the lost redo log group is ACTIVE, you should first attempt to clear the log file.
B. If the lost redo log group is CURRENT, you must clear the log file.
C. If the lost redo log group is ACTIVE, you must restore, perform cancel-based incomplete recovery, and open the database using the RESETLOGS option.
D. If the lost redo log group is CURRENT, you must restore, perform cancel-based incomplete recovery, and open the database using the RESETLOGS option.

单项选择题You issue the following command on the RMAN prompt. REPORT NEED BACKUP DAYS 5; Which statement is true about executing this command?（）

A. It will display a list of files that need incremental backup
B. It will display a list of files that need backup after five days
C. It will display a list of files that were backed up in the last five days
D. It will display a list of files that have not been backed up in the last five days
E. It will apply the current retention policy to determine the files that need to be backed up