RMAN> select name,open_mode from v$pdbs;
using target database control file instead of recovery catalogNAME OPEN_MODE
---------- ----PDB$SEED READ ONLYORA12P1 READ WRITEORA12P2 MOUNTED
RMAN> backup tablespace ora12p2:users;
Starting backup at 31-MAR-14allocated channel: ORA_DISK_1channel ORA_DISK_1: SID=137 device type=DISKchannel ORA_DISK_1: starting full datafile backup setchannel ORA_DISK_1: specifying datafile(s) in backup setinput datafile file number=00013 name=/appl/oradata/cdbroot/ORA12C1/ F5D05369C4B23E83E0430100007F6D99/datafile/o1_mf_users_9mhr0o5l_.dbfchannel ORA_DISK_1: starting piece 1 at 31-MAR-14channel ORA_DISK_1: finished piece 1 at 31-MAR-14piece handle=/appl/oradata/ flash_recovery/ORA12C1/F5D05369C4B23E83E0430100007F6D99/backupset/2014_03_31/ o1_mf_nnndf_TAG20140331T001832_9mhzdb6w_.bkp tag=TAG20140331T001832 comment=NONEchannel ORA_DISK_1: backup set complete, elapsed time: 00:00:01Finished backup at 31-MAR-14 Starting Control File and SPFILE Autobackup at 31-MAR-14piece handle=/appl/oradata/flash_recovery/ ORA12C1/autobackup/2014_03_31/o1_mf_s_843610715_9mhzdcv8_.bkp comment=NONEFinished Control File and SPFILE Autobackup at 31-MAR-14 RMAN> The above example illustrates that if root container is open and in archivelog it can do the backup of tablespace whether the pdb is mounted or open.

* The ORA_DATABASE_PARAMETER policy audits commonly used Oracle Database parameter settings. By default, this policy is not enabled.

Explanation/Reference:
Explanation:
http://docs.oracle.com/database/121/ADMIN/cdb_admin.htm

* orapwd
/ You can create a database password file using the password file creation utility, ORAPWD.
The syntax of the ORAPWD command is as follows: orapwd FILE=filename [ENTRIES=numusers] [FORCE={y|n}] [ASM={y|n}] [DBUNIQUENAME=dbname] [FORMAT={12|legacy}] [SYSBACKUP={y|n}] [SYSDG={y|n}] [SYSKM={y|n}] [DELETE={y|n}] [INPUT_FILE=input-fname]
force - whether to overwrite existing file (optional),
* v$PWFILE_users / 12c: V$PWFILE_USERS lists all users in the password file, and indicates whether the user has been granted the SYSDBA, SYSOPER, SYSASM, SYSBACKUP, SYSDG, and SYSKM privileges.
/ 10c: sts users who have been granted SYSDBA and SYSOPER privileges as derived from the
password file.
ColumnDatatypeDescription
USERNAMEVARCHAR2(30)The name of the user that is contained in the password file
SYSDBAVARCHAR2(5)If TRUE, the user can connect with SYSDBA privileges
SYSOPERVARCHAR2(5)If TRUE, the user can connect with SYSOPER privileges
Incorrect:
not E: The format of the v$PWFILE_users file is already in 12c format.

* SET_TABLE_PREFS Procedure
This procedure is used to set the statistics preferences of the specified table in the specified schema.
* Example:
Using Pending Statistics
Assume many modifications have been made to the employees table since the last time statistics were gathered. To ensure that the cost-based optimizer is still picking the best plan, statistics should be gathered once again; however, the user is concerned that new statistics will cause the optimizer to choose bad plans when the current ones are acceptable. The user can do the following:
EXEC DBMS_STATS.SET_TABLE_PREFS('hr', 'employees', 'PUBLISH', 'false'); By setting the employees tables publish preference to FALSE, any statistics gather from now on will not be automatically published. The newly gathered statistics will be marked as pending.