Problem #15

Refine the ERD from problem 14 with a generalization hierarchy consisting of Provider, Physician, and Nurse. The root of the generalization hierarchy is the Provider entity type. The primary key of Provider is ProvNo replacing the attributes PhyNo and NurseNo. The other attributes in the Provider entity type should be the attributes common to Nurse and Physician. You should rename the attributes to be consistent with inclusion in the Provider entity type. The generalization hierarchy should be complete and disjoint.