$($a$)$ Ensuring data integrity is an important issue in data design. Data integrity issues

are addressed in each and every stage of database design. According to the book,

integrity constraints "facilitate maintaining the accuracy of data in the

database." According to Merriam Webster's dictionary, synonyms for integrity

include incorruptibility, soundness, and completeness.

$($i$)$ Identify ONE $(1)$ feature used in conceptual, logical and physical design

that embody data integrity concerns.

$($ii$)$ Provide example for each phases to support your answer.

$(3$ marks$)$

$($b$)$ Read the following discourse then answer the questions that follow.

Discourse: Health Centre Application

There are many doctors assigned to treat patients at a health centre. Patients

must be registered with an associated doctor before they can book an

appointment. However a patient when attending an appointment may not always

see their own doctor, instead they may see another doctor working at the health

centre. The doctor sees the patient and he$/$she then makes a diagnosis of the

illness$/$ailment$.$ Medicines $($if required$)$ to treat the illness$/$ailment are recorded

by the doctor on a form called a prescription. There may be many medicines

recorded on a prescription and there may be many prescriptions for a patient if

they have many illnesses$/$ailments$.$ The patient is given prescriptions so that

they can collect$/$buy the medicines from a local drug store or pharmacist. The

doctor also records the details of the prescription this includes the medicine

name, the category and the dose $($amount taken and frequency$)$ and other

instructions if applicable $($eg avoid alcohol$).$ Repeat prescriptions $($where a

prescription extends over a period of time$)$ are usually sent to the patient by

post. Medicines are classified according to their use, eg flu remedies, skin

complaint remedies. Some medicines may fit into more than one category, eg

penicillin.

Produce a logical data model for the above discourse. Your model should

represent:

The entities.

The relationships.

Multiplicity of the relationships, ie cardinality and optionality.

Draft tables required $($including the primary and foreign keys$).$

Justify any modeling decisions and state any assumptions you have made.