Systems Analysis & Design 7 Edition Chapter 1

advertisement
Systems Analysis & Design
7th Edition
Chapter 1
1
Chapter Objectives
 Discuss the impact of information technology
on business strategy and success
 Define an information system and describe its
components
 Explain how profiles and models can represent
business functions and operations
 Explain how the Internet has affected business
strategies and relationships
 Identify various types of information systems
and explain who uses them
2
Chapter Objectives
 Explain modeling, prototyping, and CASE tools
 Distinguish between structured analysis and
object-oriented analysis
 Compare the systems development life cycle
waterfall model to adaptive models
 Discuss the role of the information technology
department and the systems analysts who
work there
3
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
failure
4
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
5
The Impact of Information
Technology
 The Future of IT
– Accounts for almost 30 percent of
America’s economic growth, and the
wage gaps between IT workers and all
other workers will continue to widen
– Global online population skyrocketed
between 2000 and 2005
6
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
7
The Impact of Information
Technology
 Who develops Information Systems?
–
–
–
–
–
–
–
In-house applications
Software packages
Internet-based application services
Outsourcing
Custom solutions
Enterprise-wide software strategies
How versus What
8
Information System Components
 A system is a set of related
components that produces
specific results
 A mission-critical system is
one that is vital to a
company’s operations
 Data consists of basic facts
that are the system’s raw
material
9
Information System Components
 Hardware
– Moore’s Law
 Software
–
–
–
–
System software
Application software
Enterprise applications
Horizontal system
10
Information System Components
 Software
– Vertical system
– Legacy systems
 Data
– Tables
– Linking
11
Information System Components
 Processes
– Define 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
Understanding The Business
 Business Process Modeling
 Business Profile
 Business Models
– Business model
– Business process
– Business process reengineering (BPR)
13
Understanding The Business
 New Kinds of Companies
– Production-oriented
– Service-oriented
– Internet-dependent
– Dot-com (.com)
– Brick-and-mortar
14
Impact of the Internet
 E-Commerce or I-Commerce
 B2C (Business-to-Consumer)
 B2B (Business-to-Business)
– EDI
– Extensible markup language (XML)
– Supplier relationship management (SRM)
15
Impact of the Internet
 Web-Based System Development
– WebSphere
– .NET
– Web services
16
How Business Uses Information
Systems
 In past, IT managers divided systems
into categories based on the user group
the system served
–
–
–
–
Office systems
Operational systems
Decision support systems
Executive information systems
17
How Business Uses Information
Systems
 Today, it makes more sense to identify a
system by its functions, rather than by
users
–
–
–
–
–
Enterprise computing systems
Transaction processing systems
Business support systems
Knowledge management systems
User productivity systems
18
How Business Uses Information
Systems
 Enterprise computing
systems
– Support company-wide operations
and data management
requirements
 Transaction processing
systems
– Efficient because they process a
set of transaction-related
commands as a group rather than
individually
19
How Business Uses Information
Systems
 Business support
systems
– Provide job-related
information to users at all
levels of a company
– Management information
systems (MIS)
– Radio frequency identification
(RFID)
– What-if
20
How Business Uses Information
Systems
 Knowledge management systems
– Called expert systems
– Simulate human reasoning by combining a
knowledge base and inference rules
– Many use fuzzy logic
21
How Business Uses Information
Systems
 User productivity systems
– Technology that improves productivity
– Groupware
 Information systems integration
– Most large companies require systems that
combine transaction processing, business
support, knowledge management, and user
productivity features
22
Information System Users and Their
Needs
23
Information System Users and Their
Needs
 Top managers
 Middle Managers and Knowledge
Workers
 Supervisors and Team Leaders
 Operational Employees
24
Systems Development Tools and
Techniques
 Modeling
–
–
–
–
–
–
Business model
Requirements model
Data model
Object model
Network model
Process model
25
Systems Development Tools and
Techniques
 Prototyping
– Prototype
– Speeds up the development process
significantly
– Important decisions might be made too early,
before business or IT issues are thoroughly
understood
– Can be an extremely valuable tool
26
Systems Development Tools and
Techniques
 Computer-Aided Systems Engineering
(CASE) Tools
– Also called computer-aided software
engineering
27
Systems Development Methods
 Structured Analysis
– Systems development life cycle (SDLC)
– Predictive approach
– Uses a set of process models to describe a
system graphically
– Process-centered technique
28
Systems Development Methods
 Object-oriented Analysis
– O-O analysis combines data & processes into
objects
– Object is a member of a class
– Objects possess properties
– Methods change an object’s properties
– A message requests specific behavior or
information from another object
29
Planning and Modeling a Systems
Development Project
 In addition to selecting a development
method, system developers also must
create a plan or model for the many
tasks that will be required
 Typically, the development team will use
project management tools to help
achieve the end result
30
Planning and Modeling a Systems
Development Project
 Comparison of Predictive and Adaptive
Models
– The SDLC usually is referred to as the waterfall
model
31
Planning and Modeling a Systems
Development Project
 The SDLC Waterfall Model
– Disadvantage in the built-in structure of the
SDLC, because the waterfall model does not
emphasize interactivity among the phases
– This criticism can be valid if the SDLC phases
are followed too rigidly
– However, adjacent phases usually interact
32
Planning and Modeling a Systems
Development Project
 The SDLC Waterfall Model
– Usually includes five steps
• Systems planning
• Systems analysis
• Systems design
• Systems implementation
• Systems operation, support, and security
33
Planning and Modeling a Systems
Development Project
 Systems planning
– Systems request
– Purpose of this phase is to perform a
preliminary investigation whose key part is a
feasibility study
 Systems Analysis
– First step is requirements modeling
– End product is the System requirements
document
34
Planning and Modeling a Systems
Development Project
 Systems Design
– Identify all outputs, inputs, and processes
– End product is system design specification
 Systems Implementation
– New system is constructed
– Users, managers, IT staff trained to operate
and support the system
– System evaluation performed
35
Planning and Modeling a Systems
Development Project
 Systems Operation, Support, and
Security
– A well-designed system must be secure,
reliable, maintainable, and scalable
– After several years of operation, systems need
extensive changes
– SDLC ends with system replacement
36
Planning and Modeling a Systems
Development Project
 Adaptive Methods and Models
– Attempt to develop a system incrementally, by
building a series of prototypes and constantly
adjusting them to user requirements
– Extreme Programming (XP)
– Analysts should recognize that these
approaches have advantages and
disadvantages
37
Planning and Modeling a Systems
Development Project
 Joint Application Development and
Rapid Application Development
Methods and Models
– Joint application development (JAD)
– Rapid application development (RAD)
 Other Development Methods and
Models
– Rational Unified Process (RUP®)
– Microsoft Solutions Framework (MSF)
38
Planning and Modeling a Systems
Development Project
 The Importance of Project Management
– Regardless of the development strategy,
people, tasks, timetables, and expenses must
be managed effectively
– Complex projects can involve dozens of
people, hundreds of tasks, and many
thousands of dollars
39
Systems Development Guidelines
 Stick to a plan
 Involve the users throughout the
development process
 Listening is very important
 Use project management tools to
identify tasks and milestones
 Remain flexible
 Develop accurate cost and benefit
information
40
Information Technology Department
 The information technology (IT)
department develops and maintains a
company’s information systems
 The IT group provides technical support
41
Information Technology Department
 Application Development
– Team may include users, managers and IT
Staff members
 Systems Support and Security
– Deployment team
 User Support
– Help desk or information center (IC)
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
– Webmasters
43
Information Technology Department
 Quality Assurance (QA)
– Reviews and tests all applications and systems
changes to verify specifications and software
quality standards
– Is a separate unit that reports directly to IT
management
44
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
45
The Systems Analyst Position
 Responsibilities
– Translate business requirements into practical
IT projects to meet needs
 Required Skills and Background
– Solid communication skills and analytic ability
46
The Systems Analyst Position
 Certification
 Career Opportunities
–
–
–
–
–
Job titles
Company organization
Company size
Corporate culture
Salary, location, and future growth
47
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
 Organization structure usually includes levels
48
Chapter Summary
 Systems analyst use modeling, prototyping,
and CASE tools
 Various development methodologies exist
 Regardless of the development model, it is
important to use project management tools
necessary to manage people, tasks, timetables,
and expenses
 An IT department develops, maintains and
operates a company’s information systems
49
Chapter Summary
 Systems analysts need a combination of
technical and business knowledge, analytical
ability, and communication
 Chapter 1 complete
50
Download