ENTITY RELATIONSHIP STRUCTURES
Figure drawn below contains the entity set PERSONS, which is associated with two relationship sets. One relationship set is WORK ON with projects. This relationship set shows that persons work on projects. The other relationship set, ARE IN, shows that persons are in departments. Entity set PARTS is associated with three relationship sets: USE with PROJECTS to show that projects use parts, SUPPLY with SUPPLIERS to show that suppliers supply parts, and HOLD with WAREHOUSES to show that parts are held in warehouses.