To access an Oracle server, the federated server establishes a connection to the Oracle server by using a user ID and password that are valid for that data source.
Restrictions
The user ID at the Oracle data source must be created by using the Oracle create user command with the identified by clause, instead of the identified externally clause.
Procedure
CREATE USER MAPPING FOR local_userID SERVER server_definition_name
OPTIONS (REMOTE_AUTHID 'remote_userID', REMOTE_PASSWORD 'remote_password') ;