CS206 Systems Analysis and Design
1.
What are the four advantages of using a data flow approach over narrative explanations of data movement?
A. Freedom from committing to the technical implementation of the system too early.
B. Further understanding of the interrelationships of systems and subsystems.
C. Communicating current system knowledge to users through data flow diagrams.
D. Analysis of the proposed system to determine if all the necessary data and processes have been defined.
2.
What are the four data items that can be symbolized on a data flow diagram?
They are an external entity, movement of data, the occurrence of a transforming process, a data store.
3.
What is a context diagram? Contrast it to a level 0 DFD.
A context diagram is a diagram to conceptualize data flows within an organization. It usually is a list of external entities, data flows, processes, and data stores which determines the boundary of the target system. On the other hand, a level-zero DFD is prepared to show an overview of the system including basic inputs, processes, and outputs.
4.
Define the top-down approach as it relates to drawing data flow diagrams.
An approach is to prepare DFDs for an overview of the system first, then add detailed aspects of the diagram. In other words, the diagrams move from general to specific.
5.
What is the difference between a logically and physically oriented data flow diagram?
A logically oriented data flow diagram shows how the business operates. A physically oriented data flow diagram shows how the system will be implemented using technology and manual procedures.
6.
List five characteristics found on a physical data flow diagram that are not on a logical data flow diagram.
A. Distinguishing which processes are manual and which are automated.
B. Sequencing processes in the order they must be executed.
C. Temporary data stores and transaction files.
D. Specifying actual document and file names.
E. Controls to ensure accuracy and completeness.
7.
What is partitioning, and how can it used?
Partitioning is the process of dividing a data flow diagram into manual procedures and computer programs. It is used after the physical data flow diagram has been created by examining the processes and the data flowing from one process to another.
8.
Pizza House wants to install a CUSTOMER ORDER SYSTEM (COS) to record orders for pizza and spaghetti. There are 7 processes included :
Add Customer Record , Find Customer Record , Take Customer Order ,
Print Customer Receipt , Deliver Customer Order , Send Order to Cook , and Print Weekly Totals .
The detail activities are as follows.
(a) When regular customers call Pizza House in the phone, they are asked their phone number. When the number is input, the customer information (name, address, and last order date) automatically brought up on the screen.
(b) Once the customer order is taken, the total amount , including tax and delivery, is calculated.
(c) Then the customer order is given to the cook.
(d) A customer receipt is printed. Occasionally, special offers (coupons) are printed so the customer can get a discount. Drivers who make deliveries give customers a copy of the receipt and a coupon (if any). Weekly totals are kept for comparison with last year’s performance.
(a). Draw a context diagram for Pizza House.
(b). Draw a diagram 0 (logical DFD) from (a).
CS206 Answer for Assignment 4 May 2005 Page: 1

CS206 Systems Analysis and Design you may add the entities, data flows and data stores that have not been mentioned above yourself.
9.
The Limon Car Rental Agency has a Car Rental System. It rents cars to customers at the airport. The customers can reserve, rent, and return a car in the agency.
Reserve Car i) To reserve a car, a customer provides his own personal information and gives the information of his most favorite car to the agent. ii) iii)
The agent checks for the availability of that car from the Car Master.
If the car is available, the car record is updated in the Car Master, a customer record and a reservation record are created in the Customer Master and the Reservation File respectively.
A reservation no.
is given to the customer.
Rent Car i) When a customer arrives to the agency counter at the airport, he is first asked for the reservation number if the reservation was made before. ii) Then, the reservation record is retrieved from the Reservation File. If no reservation was made, the customer provides the information of his most favorite car and the availability of the car is checked.
CS206 Answer for Assignment 4 May 2005 Page: 2

CS206 Systems Analysis and Design iii) If the car is available, his own personal information is stored in the Customer Master, the Car
Master is updated, and then, the agent creates a rental contract and stores a record in the Rental
File. iv) Next, the customer signs the contract to confirm the rental, and pays for the rental fee . v) The payment is sent to the Account Department. vi) The copy of the rental contract , a payment receipt , and the car key is given, and the customer picks up the car in the car park.
Return Car i) When a car is returned from the customer, the Rental Master and the Car Master are updated, and it is sent to Service Centre for checking. ii) Technicians in the centre check the status of the car and prepare it for the next rental. iii) If it is in good condition, the checked car is sent back to the agency.
According to the above description, draw: A Context Diagram, and A Level-0 diagram for the Car
Rental System.
Car Information Reservation No.
CUSTOMER
Customer Information
Reservation No.
Rental Fee
0
Car
Rental
System
Copy of Rental
Contract
Car Key
Car
CUSTOMER
Car
Returned Car Payment
SERVICE
CENTRE
Checked Car
ACCOUNT
DEPT
Reservation No.
Car Information
1
Reserve
Car
Car Record
CUSTOMER
Customer Information
New
Customer
Record
New
Reservation
Record
Car Information
Rental Fee
Reservation No.
Copy of Rental Contract
Car Key
Car
D1
Customer
Master
New
Customer
Record
2
Rent Car
D2
Reservation
File
Reservation
Record
Payment
Car Record
ACCOUNT
DEPT
New Rental Record
D4 Rental File
D3 Car Master
Rental Record
CUSTOMER
Car
3
Return
Car
Car Record
Returned Car
Checked Car
SERVICE
CENTRE
CS206 Answer for Assignment 4 May 2005 Page: 3