This illustration shows an example Java inheritance hierarchy and how it relates to the corresponding relational database inheritance hierarchy.

The Java inheritance hierarchy contains the following classes: The Root Class is Vechicle which owns data members id (number) and passengerCapacity (integer). Branch Classes Unfueled Vechicle and Fueled Vehicle extend the Root Class. Unfueled Vehicle owns no data members. Fueled Vehicle owns data members fuelCapacity (integer) and fuelType (string). Leaf Class Bicycle extends Branch Class Unfueled Vehcile and owns data member description (string). Leaf Class Car extends Branch Class Fueled Vehicle and owns data member description (string).

The relational database inheritance hierarchy contains the following tables: VEHICLE, FUELED_VEHICLE, BICYCLE, and CAR. The VEHICLE table contains entries for both Branch and Leaf Classes: FUELED_VEHICLE, BICYCLE, and CAR. The FUELED_VEHICLE table contains entries only for Fueled Vehicle Branch Classes. The BICYCLE table contains entries only for Leaf Class Bicycle. The CAR table contains entries only for Leaf Class Car. There is no table for Branch Class Unfueled Vehicle.