Below I have tried to summarize some comments / questions which I would like you to consider and respond when we meet:
- Explain the Patient – Doctor relationship in terms of semantics and justify why is it I:N (since a patient may be examined by several doctors during the same visit)?
- Explain both weak entity types in terms of (a) Owner entity (e.g., which entity type is the owner of Comments and Test)? (b) What exactly (in the problem description) is it that justifies the 3ary relationships (i.e., Attend and Has)
- Diagnosis. The entity appears to be totally independent of patients. Moreover, the attribute ‘comments’ is attached to the entity; this cannot be right as comments are made by doctors based on medical results of patient visits.
- The 1:1 cardinality of ‘Results’ does not include the case of a diagnosis being made on the basis of several tests. Moreover, rhe result of a test is made available once the test is actually performed. How is this modelled in the ER?
- ISA is correct, but (a) what is the primary key of FUND since there is no relevant suggestion in the problem description and (b) why did you not choose to have FUND as a multivalued attribute?
- Cardinality of Insured – FUND (a FUND may have several insured patients)
- Where do you model/keep the total cost for an uninsured patient?