Roles are the mechanism used by Oracle to facilitate the granting of system and object privileges to users. The granting of roles is a three-step process:
The role is created by someone with the CREATE ROLE system privilege.
System or object privileges are granted to the role by anyone with the proper authorization.
The role is granted to a user by anyone who has the GRANT ANY ROLE system privilege, or by anyone who has been granted the role via the WITH ADMIN OPTION.