You are probably aware that there is a new feature in Oracle Database 12c called Multitenant. Multitenant provides the ability for a single instance to manage multiple databases. At the higest level the Multitenant architecture includes:
- The Multitenant Instance - This is really my own name, for what Oracle calls the Database Instance in the documentation. I'm calling it the Multitenant Instance simply to distinguish between an instance supporting a Multitenant database and one that is not.
- A Container Database (CDB) - This is the type of database that is created when that database supports Oracle's Multitenant option. The container database is also called the ROOT container and is called CDB$ROOT within the data dictionary views of the CDB.
- The Root Container Database - This container (database) is created automatically when you create a Multitenant database. The Root container contains the data dictionary for teh CDB