Interpretation:
This slide shows the integration of three deployed applications into a single three different non-CDBs. The graphic on the slide shows a multi-tenant container database with four containers: the root and three pluggable databases. Each pluggable database has its own dedicated application, managed by its own DBA or managed by a container administrator.
Pluggable databases are a set of database schemas that logically act as a separate database for users and applications. But at the physical level, the Multitenant container database has a DB instance and database file, just like non-CDB.
A CDB groups multiple applications and ends with an instance, resulting in a set of background processes, an SGA assignment, a system data dictionary in the root container, and for all PDBs, each PDB maintains its own application data dictionary. When an application needs to be patched or upgraded, maintenance operations are performed only once on the CDB, so all applications are updated at the same time.
Points:
1. CDB and PDB share Background processes, shared/process memory, Oracle System metadata
2. Each PDB manages the user object metadata independently, and the data dictionary in the PDB contains pointers to the data dictionary in the root.
ORACLE12C Data Dictionary schema in the CDB database: http://blog.csdn.net/zhang123456456/article/details/77994483
Discussion on ORACLE12C multi-tenant CDB and PDB parameter file: http://blog.csdn.net/zhang123456456/article/details/71304921
ORACLE12 Multi-Tenant Container database schema