Relationship between PDB, CDB, and users in Oracle12c, oracle12cpdb

Relationship between PDB, CDB, and users in Oracle12c, oracle12cpdb

CDB: CDB is called the Container Database and the Container Database. (Public users)

PDB: PDB is called Pluggable Database, which is Pluggable. (Local User)

Link example:

We can clearly see the components of CDB:

1. ROOT:ROOT, also known as CDB $ ROOT, stores metadata provided by ORACLE and Common users)An example of metadata is the source code of the PL/SQL package provided by ORACLE. The Common User is the User that exists in each container. A cdb can have only one root.

2. SEED: Also called PDB $ Seed,This is the template for creating the PDBS database.You cannot add or modify an object in Seed. One CDB can have only one Seed. This sentiment is very similar to the model database in SQL SERVER.

3. PDB:The image presented by PDB to users and applications is like a normal database without CDB.. For example, a PDB can include all the data and code required to support a specific application. PDB is fully backward compatible with all databases of earlier versions of Oracle12c.

Each of these components can be called a container. Therefore,ROOT is a container, Seed is a container, and each PDB is a container. Each container has a unique ID and name in CDB.

We can easily insert a PDB to CDB or pull a PDB from CDB. When we insert a PDB into CDB, it is equivalent to connecting the PDB with CDB. Otherwise, the relationship is removed.

This greatly facilitates data migration. We can easily move a specific PDB from one CDB to another without changing any data and architecture. Of course, a PDB can only insert one CDB at a time instead of multiple. Each PDB has its own unique GUID to prevent the use of PDB.