OCP-1Z0-053-V12.02-549题

549.Which is the correct command to put the database in ARCHIVELOG mode?

A. alter database archivelog

B. alter system enable archivelog mode

C. alter database enable archive

D. alter database archivelog enable

E. None of the above

Answer: A 

答案解析： 

Changing the Database Archiving Mode

To change the archiving mode of the database, use the ALTER DATABASE statement with the ARCHIVELOG or NOARCHIVELOG clause. To change the archiving mode, you must be connected to the database with administrator privileges (AS SYSDBA).

The following steps switch the database archiving mode from NOARCHIVELOG to ARCHIVELOG:

1. Shut down the database instance.

   SHUTDOWN IMMEDIATE

   An open database must first be closed and any associated instances shut down before you can switch the database archiving mode. You cannot change the mode from ARCHIVELOG to NOARCHIVELOG if any data files need media recovery.

2. Back up the database.

   Before making any major change to a database, always back up the database to protect against any problems. This will be your final backup of the database in NOARCHIVELOG mode and can be used if something goes wrong during the change to ARCHIVELOG mode.

3. Edit the initialization parameter file to include the initialization parameters that specify the destinations for the archived redo log files .

4. Start a new instance and mount, but do not open, the database.

   STARTUP MOUNT

   To enable or disable archiving, the database must be mounted but not open.

5. Change the database archiving mode. Then open the database for normal operations.

   ALTER DATABASE ARCHIVELOG;

   ALTER DATABASE OPEN;

6. Shut down the database.

   SHUTDOWN IMMEDIATE

7. Back up the database.

   Changing the database archiving mode updates the control file. After changing the database archiving mode, you must back up all of your database files and control file. Any previous backup is no longer usable because it was taken in NOARCHIVELOG mode.

 官方参考：http://docs.oracle.com/cd/E11882_01/server.112/e25494/archredo.htm#i1006246