1.1 Overview of the Multitenant Architecture

Figure 1-1 Multi-Tenant Architecture

Description of "Figure 1-1 Multi-Tenant Architecture"

Table 1-1 Overview of the Multi-Tenant Architecture

Field	Description
Container Database	The CDB is a collection of schemas, schema objects, and non-schema objects to which all PDBs belong. Every CDB has one and only one root container named CDB$ROOT. The root stores the system metadata required to manage PDBs. All PDBs belong to the root. The system container is the CDB root and all PDBs that belong to this root. The CDB root does not store user data. Oracle recommends that you do not add common objects to the root or modify Oracle-supplied schemas in the root. However, you can create common users and roles for database administration. A common user with the necessary privileges can switch between containers.
Application Root	Consider an application root as an application-specific root container. It serves as a repository for a master definition of an application back end, including common data and metadata. To create an application root, connect to the CDB root and specify the AS APPLICATION CONTAINER clause in a CREATE PLUGGABLE DATABASE statement.
Seed PDB	Unlike a standard PDB, a seed PDB is not intended to support an application. Rather, the seed is a template for the creation of PDBs that support applications. To accelerate creation of application PDBs within an application container, you can create an application seed. An application container contains either zero or one application seed.
Application PDB	An application PDB belongs to exactly one application container. Unlike PDBs plugged in to the CDB root, application PDBs can share a master application definition within an application container. For example, a user_details table in an application root might be a data-linked common object, which means it contains data accessible by all application PDBs plugged in to this root. PDBs that do not reside within the application container cannot access its application common objects.