The State of New York certifies firefighters throughout the state and must keep track of all of them, as well as of the state’s fire departments. Each fire department has a unique department number, a name that also identifies its locale (city, county, etc.), the year it was established, and its main telephone number. Each certified firefighter has a unique firefighter number, a name, year of certification, home telephone number, and a rank (firefighter, fire lieu-tenant, fire captain, etc.) The state wants to record the fire department for which each firefighter currently works and each firefighter’s supervisor. Supervisors are always higher-ranking certified firefighters.

Construct a relational database for New York’s fire departments and firefighters.