COSC 2810
Systems Analysis and Design
● Instructor: Quinn Shao
● E-mail: qshao@webster.edu
● Online course info:
http://ereserves.webster.edu
(Electronic Reserves and Course Materials)
1
What is System Analysis and
Design?
● Step by step process developing highquality information system.
What is information system?
● Combination of 1. IT
2. People
3. data
2
Introduction
● Companies use
information as a
weapon in the battle to
increase productivity,
deliver quality products
and services, maintain
customer loyalty, and
make sound decisions.
● Information technology
can mean the difference
between success and Figure 1-1
failure
3
The Impact of Information
Technology
● Information Technology
– Combination of hardware and software
products and services that companies use to
manage, access, communicate, and share
information
– A vital asset that must be used effectively,
updated constantly, and safeguarded carefully
4
The Impact of Information
Technology
● The Future of
IT
– Responsible
for half of all
productivity
growth and a
third of all
economic
growth
between
1995-1999
Figure 1-3
5
The Impact of Information
Technology
● The Role of Systems Analysis and
Design
– Systems Analysis and Design
• Step-by-step process for developing highquality information systems
– Systems Analyst
• Plan, develop, and maintain information
systems
6
Information System Components
● A System is a set of related components
that produces specific results
● Information systems have five key
components: hardware, software, data,
processes, and people
7
Figure 1-6
Information System Components
Figure 1-9
8
Information System Components
● Hardware
– Everything in the physical layer of the
information system (server, workstation,
network, computer, devices)
– Moore’s Law accurately predicted that
computer processing power would double
every 18 to 24 months
9
Information System Components
● Software
–
–
–
–
System software (OS, security SW)
Network operating system (NOS)
Application software (Word, Access, Spreadsheets)
Enterprise applications (order processing SW, Payroll
sys.)
– Horizontal system (can be adapted for use in many
different companies, inventory sys. Payroll sys.)
– Vertical system (special purpose sys.: web-based retailer,
medical sys.)
– Legacy systems: a new sys. Must be able to exchange
data with older application)
10
Information System Components
● Data
– The raw
material that an
information
system
transforms into
useful
information
(database)
Print a paycheck
by linking
different
database tables
Figure 1-11
11
Information System Components
● Processes
– Describe the tasks and business functions that
users, managers, and IT staff members perform
to achieve specific results
● People
– Users, or end users, are the people who
interact with an information system, both inside
and outside the company
12
The primary purpose of an information system
is to provide valuable info to users.
Success or failure of a system depends on
whether user are satisfied with the sys’s output
and operations.
successful info. depends on the skilled
professionals like, sys. analyst, programmers,
DBAs.
13
Understanding The Business
IT professionals must understand a company’s business
operations in order to design successful systems. (a retail
store or a hotel chain has unique info sys. requirements)
● Business Profile
– Overview of a company ( products, service through
interview)
● Business Models
– Graphical representation of one or more business
processes
14
Figure 1-12
Understanding The Business
● New Kinds of Companies
● Companies are classified based on their
main activities:
– Production-oriented (Intel, Motorola, Cisco)
– Service-oriented (Oracle, Amazon.com, Office
Depot)
– Brick-and-mortar (traditional companies)
– Dot-com (.com)
Figure 1-14
15
Impact of the Internet
● E-Commerce (I-Commerce)
- electronic commerce
– Internet-based commerce
● B2C (Business-to-Consumer)
– Consumers can go online to purchase a variety
of products and services
● B2B (Business-to-Business)
– Enables smaller suppliers to contact large
customers and allows purchasers to obtain
instant information about market prices and
availability
(Ford buy Firestone tires, builders buy lumber)
16
Types of information system
● Today, Systems are identified by its
functions, rather than by users
–
–
–
–
–
Enterprise computing systems
Transaction processing systems
Business support systems
Knowledge management systems
User productivity systems
17
Types of information system
● Enterprise computing systems
– Information systems that support companywide operations and data management
– To integrate a company’s primary functions
(production, sales, services, inventory control,
and accounting)
Figure 1-17
18
Types of information system
● Transaction
processing systems
– Process data generated
by day-to-day business
operations: customer
order processing,
accounts receivable,
warranty, claim
processing
Figure 1-18
19
Types of information system
● Business support systems
– Provide job-related information to users at all
levels of a company (travel pattern of rental car
on holiday weekend)
– Use What-if analysis to increase profit.
(add charge to bad weather delivery or
overload delivery)
20
Figure 1-19
Types of information system
● Knowledge management systems
– Simulate human reasoning (strict logic and
fuzzy logic)
21
Figure 1-20
Types of information system
● User productivity systems
– Technology that improves productivity: e-mail,
voice mail, fax, video conference, internet to
share data
● Information systems integration
– Most large companies require systems that
combine transaction processing, business
support, knowledge management, and user
productivity features:
Combination of different types of info system.
22
Information System Team
Organization model
23
Figure 1-21
Systems Development Tools and
Techniques
● Systems analysts must know how to
use a variety of techniques such as
modeling, prototyping, and computeraided systems engineering (CASE )tools
to plan, design, and implement
information systems
24
Systems Development Tools and
Techniques
● Modeling
– A system analyst can describe and simplify an
information system by using a set of business,
data, object, and process models.
– A business model describes the info that a sys
must provide.
– A data model describes data structure and
design
– An object model describes objects (combine
data and processes)
– A process model describes the logic a
programmer uses to write modules.
25
Systems Development Tools and
Techniques
● Prototyping
– Early working version of an information system
as an initial model to evaluate finished sys.
– Speeds up the development process
significantly
– Can be an extremely valuable tool but can be
made too early before IT issues are fully
understood.
26
Systems Development Tools and
Techniques
● Computer-Aided Systems Engineering
(CASE) Tools (Tool kit part 2)
– CASE uses powerful software to help systems
analysts develop and maintain information
systems
Microsoft Visio for drawing
charts, diagrams.
Figure 1-22
27
Systems Development Methods
● Structured Analysis
– traditional systems development technique
– Uses the Systems Development Life Cycle (SDLC)
to plan, analyze, design, implement, and support an
information system. F1-25 shows a process that
accepts
input data from 2 sources and transforms it into output
data.
Figure 1-25
28
Systems Development Methods
● Object-oriented (O-O) analysis
– combines data and the processes that act on
the data into things called objects
– Systems analysts use O-O to model real-world
business processes and operations
29
Systems Development Methods
● Object-oriented (O-O) analysis
30
Figure 1-26
Systems Development Methods
● Joint Application Development and
Rapid Application Development
– JAD – Team based fact finding
– RAD – compressed version of the entire
process
(More details about JAD and RAD in Chapter 3)
31
Systems Development Methods
● Other development methodologies
– In addition to structured analysis and O-O
methodologies, you might encounter other
systems development techniques
– Microsoft Solutions Framework (MSF)
documents the experience of its own IT teams
32
The Systems Development Life Cycle
● SDLC used to plan and manage the
systems development process.
● It includes the following steps:
1.
2.
3.
4.
5.
Systems planning
Systems analysis
Systems design
Systems implementation
Systems operation and support
33
The Systems Development Life Cycle
34
Figures 1-28 & 1-29
The Systems Development Life Cycle
● Systems planning
– Purpose is to identify the nature and scope of a
problem.
– Systems request – begins the process &
describes problems or desired changes.
– Systems planning includes preliminary
investigation, which is a feasibility study that
anticipates cost and benefit. Make
recommendations on technical, economic, and
time factors.
35
The Systems Development Life Cycle
● Systems Analysis
– Purpose is to build a logical model of the new
system
– First step is requirements modeling, where you
investigate business processes and document
what the new system must do. (through
interview)
– End product is the System requirements
document.
36
The Systems Development Life Cycle
(SDLC)
● Systems Design
– Purpose is to create a blueprint that will satisfy
all documented requirements
– Identify all inputs, processes and outputs
– Avoid misunderstanding through manager and
user involvement
– End product (document) is system design
specification
37
The Systems Development Life Cycle
● Systems Implementation
–
–
–
–
New system is constructed
Implement, test, & install systems
File conversion occurs
Users, managers, IT staff trained to operate
and support the system
– System evaluation performed (if sys works
properly)
– Outcome of this phrase: system is ready for
use
38
The Systems Development Life Cycle
● Systems Operation and Support
– IT staff maintains and enhances the system
– Enhancements provide new features and
benefits
– Well-designed system will be reliable,
maintainable, and scalable
39
The Systems Development Life Cycle
● Systems Development Guidelines
– Stick to a plan, complete phases in sequence
– Involve users, fully understand user’s
requirements
– Identify milestones for proceed or reject
– Establish checkpoints to ensure project on
schedule
– Be flexible, sys development is a dynamic
process
– Provide accurate and reliable cost and benefit
information
40
Information Technology Department
● The information technology (IT)
department develops and maintains a
company’s information systems. IT
structure:
Figure 1-30
41
Information Technology Department
● Application Development
– Team may include users, managers and IT
Staff members
● Systems Support
– Provides hardware and software support
● User Support
– Provides users with technical information,
training, and productivity support
42
Information Technology Department
● Database Administration
– Database design, management, security,
backup, and user access
● Network Administration
– Includes hardware and software maintenance,
support, and security
● Web Support
– Design and construction of web pages and
presence. Important for e-commerce
43
The Systems Analyst Position
● A systems analyst investigates,
analyzes, designs, develops, installs,
evaluates, and maintains a company’s
information systems
● On large projects, the analyst works as
a member of an IT department team.
● Smaller companies often use
consultants to perform the work
44
Chapter Summary
● IT is a combination of hardware,
software, and telecommunications
systems that support business
● The essential components of an
information system are hardware,
software, data, processes, and people
● Companies are production oriented,
service oriented, or a combination of the
two.
45
Chapter Summary
● Based on their function and features,
information systems are identified
Organization structure usually includes
levels
● Systems analyst use modeling,
prototyping, and CASE tools
● Various development methodologies
exist, including structured analysis and
object-oriented analysis
46
Chapter Summary
●
●
●
The Systems Development Life Cycle
1. Systems planning
2. Systems analysis
3. Systems design
4. Systems implementation
5. Systems operation and support
An IT department develops, maintains and
operates a company’s information systems
Systems analysts need a combination of
technical and business knowledge, analytical
ability, and communication
47
Chapter 1 Complete