CPT 264 TTC Data and Process Modelling Case Study

CPT264 ASSIGNMENT #4(Data and Process Modelling Case Study)
ASSOCIATED READING
•
Read Chapter 2 and Chapter 3 in your “Systems Analysis and Design” Textbook
This is a two-part individual assignment.
You are the IT director at a university.
As part of a training program, you decide to draw a DFD that includes some obvious mistakes to see whether
your newly hired junior analysts can find them.
You came up with the DFD shown below.
©2017 Cengage Learning
What are the mistakes in this DFD?
Part 1 DFD Problem (Worth 45 points)
Based on the rules explained in this chapter, there are 7 mistakes with this diagram.
State the 7 mistakes the analysts should find in the following table:
1.
2.
3.
4.
5.
6.
7.
Part 2 Corrected DFD (Worth 55 points)
Draw a corrected DFD (addressing all 7 mistakes) in the designated section below.
Create processes, with appropriate names, as needed.
Corrected DFD:
Assignment Submission Steps:
1. Save your document with name, LastnameFirstnameAssignment#
2. Submit in the Assignment folder in D2L.
a. All items (DFD Problem and Corrected DFD) MUST be comprised in a single Word file.

HOWARD GOULD
SYSTEMS ANALYSIS
AND DESIGN
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2
Systems Analysis and Design
1st edition
© 2016 Howard Gould & bookboon.com
ISBN 978-87-403-1417-5
Peer review: Dr. Amin Hosseinian Far at Leeds Beckett University
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3
SYSTEMS ANALYSIS AND DESIGN
Contents
CONTENTS
Acknowledgements
7
Foreword
8
1 Introduction to systems analysis and design
9
1.1
What is an information system?
9
1.2
The system development life cycle
12
1.3
Summary
21
2
Systems analysis
23
2.1
Requirements modelling
23
2.2
Functional decomposition
24
2.3
Identifying functions and processes
25
2.4
Dataflow diagram notation
28
2.5
Drawing a physical DFD
31
2.6
DFD errors
33
2.7
Drawing a logical DFD
37
2.8
Levelled data flow diagrams
40
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SYSTEMS ANALYSIS AND DESIGN
Contents
2.9
The context (level 0) diagram
43
2.10
The data dictionary
44
2.11
Process specification
46
2.12
Decision trees
46
2.13
Decision tables
47
2.14
Structured English
50
2.15
Requirements catalogue
53
2.16
Summary
56
3
Object oriented analysis
57
3.1
Objects and classes
58
3.2
Use case modelling
63
3.3
Class diagram
69
3.4
Sequence diagrams
70
3.5
State machine diagrams
72
3.6
Activity diagrams
73
3.7
Business process modelling
74
3.8
Summary
76
4
Systems design
77
4.1
Data design
78
4.2
Entity modelling
80
4.3
Normalisation
86
4.4
Identifying relations
91
4.5
Data table structures
95
4.6
Human-computer interaction
98
4.7
System architecture
108
4.8
Network topology
111
4.9
Design documentation
114
4.10
Summary
115
5
Systems implementation
116
5.1
Software design
117
5.2
Software development and testing
123
5.3
Documentation and training
124
5.4
System changeover
125
5.5
Summary
128
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SYSTEMS ANALYSIS AND DESIGN
Contents
6
Systems maintenance
129
6.1
User support and training
129
6.2
Software maintenance
130
6.3
System performance
131
6.4
System security
132
6.5
System termination
135
6.6
Summary
135
7
Bibliography
136
8
Appendices
139
8.1
Appendix A – Cost benefit analysis
139
8.2
Appendix B – Normalisation template
142
8.3
Appendix C – Project Management
143
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SYSTEMS ANALYSIS AND DESIGN
Acknowledgements
ACKNOWLEDGEMENTS
I should like to express my gratitude to Dr. Amin Hosseinian Far at Leeds Beckett University
(formerly known as Leeds Metropolitan University) for reviewing the manuscript. The idea
for this book evolved from teaching systems analysis and design to undergraduate computing
students for many years.
The majority of the modelling diagrams presented in this book have been drawn using the
QSEE SuperLite v1.1.2 CASE tool which is free to download from http://www.leedsbeckett.
ac.uk/qsee/
Trademarks
Some of the product and company names used in this book have been used for the purpose
of identification only and may be trademarks or registered trademarks of their respective
manufacturers and sellers.
PRINCE2® is a registered trademark of AXELOS Limited.
Oracle is a registered trademark of Oracle Corporation and/or its affiliates.
Microsoft is a registered trademark of Microsoft Corporation in the United States and/or
other countries.
SSADM is a registered trademark of the Office of Government Commerce (OGC) an office
of the UK treasury.
Unified Modelling Language and UML are either registered trademarks or trademarks of
Object Management Group, Inc. in the United States and/or other countries.
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SYSTEMS ANALYSIS AND DESIGN
Foreword
FOREWORD
This book has been written to provide a concise introduction to systems analysis and design
for students studying computing, IT or business related courses. Similarly, others who need
to work with systems analysts, designers or software developers when commissioning or
whilst using a new information system may benefit from an understanding of this content.
The information is presented in a form that makes it easy to grasp the essential principles
and techniques and to apply these within an information system development project.
Contents cover the full system development life cycle and include systems analysis using
structured analysis techniques and object modelling with the unified modelling language
(UML). The newer agile approaches to systems development are also introduced. Also
included is system design, incorporating data design, human computer interaction and
system architectures, along with coverage of system implementation and maintenance. A
brief introduction to IT project management techniques is also included as an appendix.
Further supporting materials can be found at the author’s website http://howard-gould.co.uk/.
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SYSTEMS ANALYSIS AND DESIGN
Introduction to systems analysis and design
1 INTRODUCTION TO SYSTEMS
ANALYSIS AND DESIGN
On completion of this chapter you should be able to:
•
•
•
•
identify the components of an information system
understand the purpose of systems analysis
be aware of the role of the systems analyst
understand the systems development life cycle.
Information technology (IT) based information systems (IS) are essential to all types of
organisations and in order for these systems to be of benefit they must be based on well-defined
requirements and designed and built using systems analysis and design (SAD) processes.
1.1
WHAT IS AN INFORMATION SYSTEM?
An information system can be defined as a set of interrelated components that function to
provide required information for a specified purpose.
A system receives input data which is processed, resulting in meaningful information –
output. (In some cases this output may be data to be used as input to another system). An
information system, shown in Fig 1.1 below, will have a control mechanism which regulates
the inputs and processes based on feedback from the outputs. A thermostat which regulates
a heating system is a good example of this. Systems work within boundaries and operate
within an environment. Large systems may comprise a number of sub-systems which work
together to support the overall function of the main system.
Input: Data
Feedback
Control
Output: Information
Processes
Storage
Fig 1.1 Elements of an Information System
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SYSTEMS ANALYSIS AND DESIGN
Introduction to systems analysis and design
The following diagram illustrates the basic elements of a payroll system. In this example,
typical inputs would include an employee’s hours worked and their tax code. This data,
along with previously stored data such as pay rates and employee details, would be used
within system processes such as “Calculate Tax” and “Calculate Pay” in order to calculate
the employees’ pay. Some of these calculated pay details would also be used as feedback
which will be used to influence future calculations for tax etc.
Here the system boundary relates to the business and its employees using the system. However,
the environment it operates within includes outside agencies such as the tax agency.
Control
Input:
Calculate Pay
Output:
Hours
Worked,
Calculate Tax
Monthly
Pay
Details
Tax Code
Employee Details
Pay Rates
Fig 1.2 Example Payroll System
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SYSTEMS ANALYSIS AND DESIGN
Introduction to systems analysis and design
The main components of an information system are:Input – the data that comes from the environment that the system will be operating in.
Process – operates on the inputs and transforms them into outputs, e.g. an application for a
driving licence results in a driving licence being issued following processing.
Storage – for data/information.
Output – the results of a process.
Feedback – an output that is fed back into the system to alter the control of the processes.
Control – regulates the system using the ‘feedback’ to ensure the system operates
to meet its purpose.
Boundary – the limit or scope of the system.
Environment – the area in which the system operates. This may include other systems or
other organisations.
Hardware – the computers and other data input and output devices.
Software – Programs, operating systems.
Data – input values and information output.
Communication – networking infrastructure, the Internet.
People – system analysts, software developers, system users.
A number of stakeholders are involved in the system development process, including:
System requester – usually a client or senior manager
System user – person who will use the system
System analyst – person who analyses and designs information systems
System developer – person who designs, produces and tests software.
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SYSTEMS ANALYSIS AND DESIGN
1.2
Introduction to systems analysis and design
THE SYSTEM DEVELOPMENT LIFE CYCLE
The traditional approach to acquiring an information system is to use structured analysis
processes within the system development life cycle (SDLC). Structured analysis relies on
process models which show how data flows into a system and is processed by applying
business rules, which in turn leads to data being output as required information. The systems
analyst (SA) plays a leading role throughout the systems development process. A systems
analyst needs good analytical skills in order to identify problems and consider effective
solutions, and should also have good communication and interpersonal skills in order to
communicate effectively with a wide range of stakeholders ranging from senior managers
to operational employees (system users).
In recent times newer development approaches have become more team-based, utilising both
IT staff and system users to help speed up the process and so cut costs. Joint application
design (JAD) involves a group of users meeting intensively with systems analysts to help
with the information gathering and the system requirements definition process. Similarly,
rapid application development (RAD) (Martin, 1991) aims to speed up the SDLC, with
users being involved in the design and development tasks in a more interactive, iterative
way, which means that users can give feedback much sooner on the developed system than
in the traditional SDLC.

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