December 1999
SA205 : SYSTEMS ANALYSIS

QUESTION 4

Total Marks: 15 Marks

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Question 4

(a)

Define the term data flow diagram .
A data flow diagram shows the flow of information (1mark)through an information system (1mark).
Other valid answers should also receive credit.

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(b)

Consider the following scenario: Orders are received from customers and validated against the stock file to see if all the items exist.If an item does not exist,then it is added to the stock file. Each order is then checked for availability.Orders that can be supplied immediately have the order details sent to to the warehouse,and the stock file is decremented accordingly.Orders that cannot be satisfied immediately are placed in a back orders file and a requisition note is sent to the purchasing department for the missing items.If the items are no longer supplied,the purchasing department sends back a ‘not supplied ’note and the items are deleted from the stock file. When the items are received from suppliers,the goods inward department completes a ‘goods inward ’note and the stock file is incremented. Once a year there is a stock audit which results in an audit report to the warehouse manager.Any items not ordered in the last year are deleted from the stock file.Any items for which there is a discrepancy between the physical stock and the stock file have their stock level adjusted on the stock file.

(i)Identify five entities associated with the above scenario.[3 marks ]
(i)If the candidate names five entities correctly,award three marks.Deduct one mark for each error or omission.
•Warehouse manager.
•Customers.
•Goods inward department.
•Purchasing department.
•Warehouse.

(ii)Identify five processes associated with the above scenario.[3 marks ]
(ii)If the candidate names five processes correctly,award three marks.Deduct one mark for each error or omission.
•Audit stock.
•Update stock.
•Receive orders.
•Check availability.
•Delete items.

(iii)Identify two data stores associated with the above scenario.[1mark ]
One mark should be awarded for naming both data stores.
•Stock.
•Back order.

(iv)Using these entities,processes and data stores,draw a data flow diagram for the above scenario.[6 marks ]


One mark should be awarded for the correct representation of each process;a further ‘bonus ’mark should be awarded for the diagram as a whole.

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