Introduction of Multitenant Architecture

Common users and Local users: This concept came with Oracle Database 12c.

Common Users: a Common user is a user which have the same username and password authentication across PDBs of CDB.

Common users are created at CDB level and the common user can connect to the root and perform operations. By giving proper privileges to common users we can perform operations in PDBs too. Operations can be like granting privileges to local users of PDBs. A common user is a database user that has the same identity in the CDB root and in every existing and future PDBs in the CDB, or in an application root and in every existing and future application PDBs in the application container. An application common user does not require a prefix like a CDB common user.

Common users can be created in CDB$ROOT or in the application container.

Local Users: Local users are PDB specific users. We can have the same local name in PDBs.

Creating Common Users 

We can create common users using CONTAINER=ALL clause in creating user statement.

Oops.. It gives me an error invalid common user or role name.

Note: A common users name must start with ‘C##’ prefix.

Let’s try it again ..!!!

While creating application common users we need to be connected to Application Container and when we synchronize application pdb, application common users will be replicated to Applications PDBs.

We can check common users from CDB_USERS view where common=’YES’

We can see our recently created user here.

Common Roles in CDB :

We can create a common role by giving CONTAINER=ALL clause in CREATE ROLE statement.

Common Role name must start with C## prefix

We can check common roles from CDB_ROLES view.

Granting Permission to common roles and common users :

First I’m granting connect privilege to recently created role C##ROLE1 with a container=all clause.

Now I’m granting C##ROLE1 to C##AA1 user.

Profile: We can create the common profile using create the profile and container=all statement.

Stay tuned for More articles on Oracle Multitenant

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