Container and Pluggable Databases

Pluggable Database is the new feature and allows the DBA to consolidate larget number of small database applications departmental applications into a single larger RDBMS installation.  It's a set of database schemas that appears logically to users and applications as a separate database.  The Oracle Metadata and user data are totally separated into two sections.  One is Container DB (CDB) stores metadata and One is Pluggable DB(PDB) which stores user data.  This will reduce significant percentage of hardware deployment, patch and upgrade, instance and storage overhead and DBA time.

With Oracle 11g, there are non container databases and share nothing.  As a result, there are too many background processes with high shared memory and many copies of Oracle metadata.  When you need to upgrade/patch the database applications, it's time consuming as you have to upgrade each database.

Benefits of Pluggable Databases (PDBs):
Multiple databases in a centrally managed platform
Easy and Fast provisioning, patching and upgrading time savings
Central Management and administration of databases (backups, restore, disaster recovery, patching/upgrading)
Secure separation of duties (the administrator of an application can do all the required tasks, but cannot see other PDBs in the same Container Database(CDB)

From the Enterprise Manager
A Container Database (CDB) can be defined as target and a Pluggable database can be setup as a sub target of a CDB target.  After the creation of the Oracle database, only objects in the data dictionary ar the Oracle-supplied objects.

Create a new CDB either via DBCA or SQLPLUS:

• Configure an instance with init.ora parameter file then STARTUP NOMOUNT.  Be sure to check (DB_NAME, CONTROL_FILES, DB_BLOCK_SIZE, _ENABLE_PLUGGABLE_DATABASE=TRUE
• Create CBD using the CREATE DATABASE command with a new clause ENABLE PLUGGABLE DATABASE.  This will create the root container with the control files during the mount phase, the redo log files and root data files.  The root data files are used for the SYSTEM (metadata & dictionary) and SYSAUX (AWR).  It also create the seed pluggable database with its own data files used for SYSTEM and SYSAUX.  The FILE_NAME_CONVERT, like RMAN clone, to rename the data files of the seed pluggable database while copying from the root container to another location (see demo below)

SQL> connect / as sysdba
SQL > Startup nomount
SQL > Create database ORDER user sys identified by passcode user SYSTEM identified by passcode2 EXTENT MANAGEMENT LOCAL DEFAULT TEMPORARY TABLESPACE temp UNDO TABLESPACE UNDOTBS DEFAULT tablespace users ENABLE PLUGGABLE DATABASE

Create Pluggable database:

SQL> create pluggable database GLS admin user admin identified by admin file_name_convert= ('/pdbseed/','gls/');

Pluggable database created


SQL> alter pluggable database GLS open;

If you create the database with DBCA, then select the "Create As Container Database"