Which type of authentication requires user and privileges to be defined?

Internal authentication is the method by which Teradata manages user accounts and their associated privileges within its own database system. This type of authentication requires that users be explicitly defined in the database, along with the privileges they hold, which can include access rights to certain tables, views, or other resources.

In internal authentication, the database administrator is responsible for creating user accounts and granting permissions directly through the Teradata system. This ensures a controlled environment where all access is logged and managed internally, making it easier to enforce security policies.

Other types of authentication may involve external systems or third-party services where user details and privileges are managed outside of Teradata. For instance, external authentication typically relies on external directories or services to authenticate users, meaning the user and privileges are defined elsewhere rather than being stored within the Teradata system itself. Similarly, federated authentication involves integrating with other identity management systems, rather than relying on Teradata's internal user management. Third-party authentication also involves mechanisms that do not directly manage users and privileges inside Teradata.

Therefore, internal authentication is unique in its requirement for the explicit definition of users and privileges within the Teradata ecosystem, providing direct control over access and security.