The BeneCO database consists of $4$ tables: EMPLOYEE, BENEFIT, JOB, and PLAN with the following relationships:

EMPLOYEE has a primary key EMP$\_$CODE and a foreign key JOB$\_$CODE.

BENEFIT has a composite primary key EMP$\_$CODE $+$ PLAN$\_$CODE.

JOB has a primary key JOB$\_$CODE with no foreign keys.

PLAN has a primary key PLAN$\_$CODE with no foreign keys