systems analysis & design 5 th edition chapter 1 introduction to systems analysis and design
TRANSCRIPT
Systems Analysis & Design
5th Edition
Chapter 1
Introduction to Systems Analysis and Design
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Chapter Objectives Discuss information technology Define an information system and
explain its components Use profiles and models to understand
business functions and operations Identify various types of information
systems and explain who uses them
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Chapter Objectives Explain systems development
tools, including modeling, and prototyping
Describe the systems development life cycle
Discuss the role of the information technology department and the systems analysts who work there
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IT, Information TechnolgyInformation system
are used to increase productivity, deliver quality products and services, maintain customer loyalty, and make sound decisions.
Figure 1-1
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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
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Vocabulary Business rule – The collection of
practices that describe how an enterprise really functions.
Policy – written business strategy that may not be a practice
Procedures – tasks performed to achieve specific results
Practice – observable actions carried out
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The Impact of Information Technology The Role of Systems Analysis and
Design Systems Analysis and Design
Step-by-step process for developing high-quality information systems
Systems Analyst Plan, develop, and maintain information
systems
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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
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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 Information systems have five key
components: hardware, software, data, processes, and people
Figure 1-6
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Information System Components
Figure 1-9
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Hardware Everything in the physical layer of the
information system Moore’s Law accurately predicted that
computer processing power would double every 18 to 24 months
Information System Components
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Information System Components Software
System software Network operating system Application software Enterprise applications Horizontal system Vertical system Legacy systems
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Information System Components
Data The raw
material that an information system transforms into useful information
Figure 1-11
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Information System Components What is a Process?
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
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Understanding The Business Business Profile
Overview of a company Business Models
Graphical representation of one or more business processes
Figure 1-12
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How Business Uses Information Systems
Enterprise computing systems Information systems that support company-
wide operations and data management
Figure 1-17
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How Business Uses Information Systems Transaction
processing systems Process data
generated by day-to-day business operations
Figure 1-18
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How Business Uses Information Systems
Business support systems Provide job-related information to
users at all levels of a company Management information systems
(MIS) What-if
Figure 1-19
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How Business Uses Information Systems Knowledge management systems
Simulate human reasoning
Figure 1-20
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How Business Uses Information Systems User productivity systems
Technology that improves productivity Word processing is an example
Information systems integration Most large companies require systems
that combine transaction processing, business support, knowledge management, and user productivity features
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Information System Users and Their Needs Executive or Top managers Middle Managers and Knowledge
Workers Supervisors and Team Leaders Operational Employees
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Systems Development Tools and Techniques Systems analysts must know how to
use a variety of techniques such as modeling, prototyping, and computer-aided systems engineering tools to plan, design, and implement information systems
Systems analysts work with these tools in a team environment
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Systems Development Tools and Techniques Modeling
A systems analyst can describe and simplify an information system by using a set of business, data, object, and process models.
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Systems Development Tools and Techniques Prototyping
Early working version of an information system
Speeds up the development process significantly
Can be an extremely valuable tool
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Systems Development Tools and Techniques Computer-Aided Systems
Engineering (CASE) Tools CASE uses powerful software to help
systems analysts develop and maintain information systems
Figure 1-22
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Systems Development Methods
Structured Analysis traditional systems development
technique Uses the systems development life cycle
to plan, analyze, design, implement, and support an information system
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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
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Systems Development Methods Object-oriented (O-O) analysis
Figure 1-26
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Systems Development Methods Joint Application Development and
Rapid Application Development JAD – Team based fact finding RAD – compressed version of the
entire process
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The Systems Development Life Cycle SDLC used to plan and manage the
systems development process. It includes the following steps:
1. Systems planning2. Systems analysis3. Systems design4. Systems implementation5. Systems operation and support
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The Systems Development Life Cycle Systems planning
Purpose is to identify the nature and scope of the business opportunity or problem
Systems request – begins the process & describes problems or desired changes
Systems planning includes preliminary investigation whose key part is a feasibility study
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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
End product is the System requirements document
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The Systems Development Life Cycle Systems Design
Purpose is to create a blueprint that will satisfy all documented requirements
Identify all outputs, inputs, and processes
Avoid misunderstanding through manager and user involvement
End product is system design specification
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The Systems Development Life Cycle Systems Implementation
New system is constructed Write, test, & document programs File conversion occurs Users, managers, IT staff trained to
operate and support the system System evaluation performed
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The Systems Development Life Cycle Systems Operation and Support
IT staff maintains and enhances the system
Maintenance changes correct errors and adapt to changes in the environment
Enhancements provide new features and benefits
Well-designed system will be reliable, maintainable, and scalable
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The Systems Development Life Cycle Systems Development Guidelines
Stick to a plan Involve users Identify milestones Establish checkpoints Be flexible Provide accurate and reliable cost and
benefit information
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Information Technology Department The information technology (IT)
department develops and maintains a company’s information systems
Figure 1-30
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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
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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
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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
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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.
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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
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Chapter Summary 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
Chapter 1 Complete