Designing a Database $($Entity Relationship Modeling

You have been asked to design a database of an information system to support a medical clinic. The system needs to keep details of Patients, Doctors, Examinations and Examination Rooms. A Doctor can be responsible for examining a number of patients, or none; each patient can receive zero or more than one examination, and each examination can take place in one or more rooms, but must be in at least one room. Here are the entities and an initial list of attributes for each:

Patient $($Patient$\_$ID$,$ Patient$\_$Name, Patient$\_$Tel$)$

Doctor $($Doctor$\_$ID$,$ Doctor$\_$Name, Doctor$\_$Specialty$)$

Examination $($Doctor$\_$ID$,$ Patient$\_$ID$,$ ExaminationRoom$\_$ID$,$ Date, Time, MedicalNote$)$

ExaminationRoom $($ExaminationRoom$\_$ID$,$ E$\_$Room$\_$Type, Building$\_$ID$,$ Floor$)$

Draw an $($initial$)$ Entity Relationship Diagram representing the entities and the relationships above.