5) Hospital Management System ER Diagram:

                                    +-------------+
                                    |   Patient   |
                                    +-------------+
                                    | patient_id (PK)|
                                    | name        |
                                    | dob         |
                                    | address     |
                                    +-------------+
                                            |
                                            |
                                  +---------+---------+
                                  |                   |
                          +-------+-------+   +-------+-------+
                          |    Admits     |   |    Doctor     |
                          |               |   +---------------+
                          +---------------+   | doctor_id (PK)|
                          | admit_id (PK) |   | name          |
                          | patient_id (FK)|  | specialization|
                          | doctor_id (FK)|   +---------------+
                          | admit_date    |
                          | discharge_date|
                          +---------------+