The hr schema exists in databases, BOSTON and DENVER, with the same password, HR. You have CREATE DATABASE LINK and CREATE SESSION privileges in both databases.
DENVER is defined as a service name in the tnsnames.ora of both databases.
You plan to use this command:
CREATE DATABASE LINK hr link CONNECT TO hr IDENTIFIED BY hr USING ' DENVER'
What must be done to ensure that all users in BOSTON can access the hr schema in DENVER?