Creating Pluggable Database in 12c.

I'll create a Pluggable database 'PDBTEST' with the help of Seed container template.

Create datafile directory for new Pluggable database.
[oracle@test pdbseed]$ mkdir -p /u01/app/oracle/oradata/cdb12c/pdbtest/


SQL> show con_name

CON_NAME
------------------------------
CDB$ROOT


SQL> create pluggable database pdbtest
  2  admin user testadmin identified by oracle
  3  roles=(dba)
  4  file_name_convert=('/u01/app/oracle/oradata/cdb12c/pdbseed/','/u01/app/oracle/oradata/cdb12c/pdbtest/');

Pluggable database created.

Lets configure the Tnsnames.ora and Listener.ora file for newly created Pluggable database.

[oracle@test admin]$ vim listener.ora

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = TCP)(HOST = test.oracle.com)(PORT = 1521))
      )
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
      )
    )
  )

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PDBORCL)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/db_1)
    )
    (SID_DESC =
      (SID_NAME = PDBTEST)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/db_1)
    )

  )  


[oracle@test admin]$ vim tnsnames.ora

PDBTEST =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = test.oracle.com)(PORT = 1521))
    )
    (CONNECT_DATA =
    (SERVICE_NAME = pdbtest.oracle.com)
    )
  )


PDBORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = test.oracle.com)(PORT = 1521))
    )
    (CONNECT_DATA =
    (SERVICE_NAME = pdborcl.oracle.com)
    )
  )

CDB12C =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = test.oracle.com)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = cdb12c.oracle.com)
    )
  )

Now check the container status.
 
SQL> select CON_ID,NAME from v$pdbs;

    CON_ID NAME
---------- ------------------------------
         2 PDB$SEED
         3 PDBORCL
         4 PDBTEST

SQL> select pdb_name, status from cdb_pdbs;

PDB_NAME             STATUS
-------------------- -------------
PDBORCL              NORMAL
PDB$SEED             NORMAL
PDBTEST              NEW

SQL> select NAME,CON_NAME,CON_ID from v$active_services;

NAME                 CON_NAME                           CON_ID
-------------------- ------------------------------ ----------
pdbtest.oracle.com   PDBTEST                                 4
pdborcl.oracle.com   PDBORCL                                 3
cdb12cXDB            CDB$ROOT                                1
cdb12c.oracle.com    CDB$ROOT                                1
SYS$BACKGROUND       CDB$ROOT                                1
SYS$USERS            CDB$ROOT                                1

6 rows selected.


SQL> select name, open_mode from v$pdbs;

NAME                           OPEN_MODE
------------------------------ ----------
PDB$SEED                       READ ONLY
PDBORCL                        READ WRITE
PDBTEST                        MOUNTED

SQL> alter pluggable database pdbtest open;

Pluggable database altered.

SQL> select name, open_mode from v$pdbs;

NAME                 OPEN_MODE
-------------------- ----------
PDB$SEED             READ ONLY
PDBORCL              READ WRITE
PDBTEST              READ WRITE

SQL> conn sys/oracle@pdbtest as sysdba
Connected.

SQL> show con_name

CON_NAME
------------------------------
PDBTEST

SQL> select tablespace_name from dba_tablespaces;

TABLESPACE_NAME
------------------------------
SYSTEM
SYSAUX
TEMP


HTH. :)