Question 5:

a) Draw the REA (Resources-Events-Agents) diagram complete with cardinalities for the following relationships of a business selling home electrical appliances:

i) Online sales can have multiple orders and each order can be associated with one or more sales. Walk in customers however to not need to place an order. Draw the REA diagram between Sales and Take Customer Order.

ii) Walk in customers can pay by cash or credit card. Draw the REA diagram for Sale and Receive Cash

iii) The suppliers deliver the inventory and send a monthly bill for merchandise delivered. The supplier does not accept or allow installment payments. Draw the REA diagram for Receive Inventory and Cash Disbursements. (12 marks)

b) Compare and contrast a data warehouse with a relational database management system. Explain when each system would be appropriate for a business. (8 marks)