Oracle Database 12c - CDB and PDB

12c New features

Multitenant Acrchitecture - single container database (CDB) to host multiple separate pluggable databases (PDB)

CDB - Container Database - You can create CDB through DBCA or manual command mode.

PDB - Pluggable Database - You can create PDB through DBCA or manual command mode.

SQL> show pdbs - lists all pdb's present in cdb

SQL> show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 DX12P                          READ WRITE NO

Oracle Database 12c introduces a new privilege called "set container".

You can access root or cdb or pdb through sqlplus connect command or alter session set container

conn system/****@db12c - connect to cdb database

conn system/****@db12p - connect to pdb database

conn system/****@"localhost:1521/db12p - connect to pdb database

SQL> alter session set container=cdb$root; - command to set root container

SQL> alter session set container=db12p; - command to set db12p container.