1.Unispare is a retailer of computer equipment. It uses a standard purchase order form when buying goods from its suppliers. The form contains the order detail (order number, order date, supplier name and address) and the list of ordered parts detail (the part number, part description and quantity ordered).

i.

a.Identify all relevant entities in the above and allocate the associated attributes of these entities.

b.Create an Entity Relationship Diagram (ERD) for the purchase order, showing the participating entities, relationship names and their degree of relationships.

ii.

A payment term (payment Term number and payment term, i.e., Cash on Delivery/7 days/30days/45 days) and contact staff (staff number, staff name) are also specified in the purchase order form.

a.Identify the relevant entities and allocate the associated attributes of these new entities.

b. Derived an Entity Relationship Diagram (ERD) for the above. Show the entities and their degree of relationships.

iii.

Represent all the above ERD described in step (i) and (ii) above as a single ERD. Provide any assumptions necessary to support your answers.

2.Describe how a fan trap and chasm trap may occur in an ERD and explain how they can be resolved. Use diagrams to support your answer.

3.Basic concepts of ER modeling are not sufficient to represent requirements of newer, more complex applications, thus additional data modeling concepts called specialisation and generalisation are incorporated into this model. However, there are two constraints that may apply to a specialization/generalization relationship; participation constraints and disjoint constraints. Define the bolded term.