Exam 1z0-062 topic 1 question 320 discussion

The HR schema exists in two databases, BOSTON and DENVER, and has the same password, HR.
You have the CREATE DATABASE LINK and CREATE SESSION privileges on both the database.
BOSTON is defined as a service name in the tnsnames.ora of both the databases.
You plan to use the command:
CREATE DATABASE LINK hr_link CONNECT to hr IDENTIFIED BY hr USING 'denver';
What must be done to ensure only the HR user in the BOSTON database can access the HR schema in the DENVER database?