All external roles mapped to the user are to be made active for the session.
The EXTERNAL keyword is useful only for directory users who are mapped to both a Teradata Database user object and one or more external role objects in the directory, where the system defaults to the privileges for the mapped user.
If the directory user is mapped only to external role objects and not mapped to a database user object, all the external roles are active by default.
Example: Enabling All Roles
This request specifies that all roles and their nested database roles that have been granted to the user become current and active for a session.
SET ROLE ALL;