One of Oracle12’s key new features is the container database, also called the plugable database, or CDB’s…container database.

New name and name on price list: Multitenent DB.

Lets look at the ‘c’ in Oracle12c.

  1. C can stand for Container. The container database contains up to 252 other databases!
  2. C can stand for Consolidation. This allows for the container DB to be setup with RAC, backup/recovery scenarios/etc…and all the attached databases pick up the architecture. Also, consolidation allows for better management for upgrades, patches, etc…the container is patched/upgraded and again all the attached DBs are upgraded and patched. The container can be maintained and the attached databases get the changes (administration consolidation). And last…consolidation is only 1 set of Oracle executables for quite a number of actual application databases.
  3. C stands for Cloud. This new architecture allows Oracle to better manage resources in the cloud.


The root database contains the metadata, common users, common resources for the and is called the CDB or the ‘container database’. The PDB’s are the application DB’s…just like non-container DB’s (the current setup with Oracle11g and prior DB’s). The Seed database is used for a template for any new PDBs to be added to this container DB.

When planning to go to this new environment:

  1. Review and rename common schema names
  2. Review and rename common synonym names
  3. Supports only Oracle12 DB’s

Oracle12 release 2…this will be the default installation option. I will blog some other useful tips in the future on CDB/PDB’s but for now, this is Oracle’s direction with their database product.

This architecture should aid the DBA staff the most:

  1. PDB’s can be setup for RAC, Standby DB, backup/recover/uptime strategies…
    1. ANY database then ‘plugged into’ the CDB inherits these attributes

  2. Machine sizing and management of processes will be greatly simplified. The CDB will have 1 set of Oracle background processes…instead of the current 1 set of processes for each database.
  3. Oracle patch management/upgrades will be greatly simplified. The DBA will patch or upgrade the CDB and all the assigned PDB’s get upgraded automatically!

This is Oracle’s direction for platform, cloud, and database management. Embrace it, don’t fear it…the multitenent DB is your friend. This new environment shouldn’t be very different for the developer and it should greatly simplify some of the current tedious tasks performed and administered by the DBA.


Dan Hotka
Oracle ACE Director