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Systems Development Environment
Chapter 1Modern Systems Analysis &
Design
Chapter 1 Learning Objectives Define information systems analysis and design Describe different types of information systems Describe Systems Development Life Cycle (SDLC) Explain Rapid Application Development (RAD),
prototyping, Joint Application Development (JAD), and Computer Aided Software Engineering (CASE)
Describe agile methodologies and eXtreme programming
Explain Object Oriented Analysis and Design and the Rational Unified Process (RUP)
Today’s Agenda What is SA&D? What Does a Systems Analyst Do?
– Skills– Participants in Systems Development– What Goes Wrong
Systems Development Methodology– What is a Methodology– For What Types of Systems is a
Methodology Used?– Traditional Systems Development Process
(SDLC)– Other Methodologies
Information Systems Analysis and Design
The complex organizational process whereby computer-based information systems are developed and maintained.
What Does a Systems Analyst Do? Studies the problems, needs, and opportunities
of an organization Determines how people, methods, “computer
technology,” and organizational methods can work together to best improve the business
Responsible for developing efficient methods for capture, movement, processing, and storage of data
Bridges technology and organization Central member of team (of various
stakeholders)
What Skills Does an Analyst Need?A Starter Set Analytical skills
– Systems thinking– Understanding business/organization via
general and firm-specific knowledge– Identifying problems/opportunities– Analyzing and solving
problems/opportunities
Systems Thinking: A General Depiction of a System
Systems Thinking: Fast-Food Restaurant
More Systems Thinking:O = f(I,P,S) Model of a System
Process
Inputs Outputs
Storage
More Systems Thinking: Design/Reengineering
C1
C2
C3
C4
C5
C6
System A:
C1
C2
C3
C4
C5
C6
System B:
System simplification concepts:
Which system is more
•Cohesive
•Decoupled
What Is Systems Thinking? Looking at a situation as a system of
interacting components – abstracting, decomposing
Identifying problem and designing selecting, implementing a solution – simplifying, reengineering internals of
(i.e., processes) and interactions between components – including interfaces, using cohesion, decoupling
What Skills Does an Analyst Need?A More Complete Set Analytical skills
– Systems thinking– Understanding business/organization via general and firm-specific
knowledge– Identifying problems/opportunities– Analyzing and solving problems/opportunities
Technical skills– Structuring requirements– Designing databases, forms, reports, navigational interfaces
Management skills– Resource management– Project management– Risk management– Change management
Interpersonal skills– Communicating– Working in teams– Facilitating groups– Managing expectations
Who Are the Players in Systems Development? User(s) Business manager(s) Steering committee Application programmers System programmers Database, network, and other technology
specialists Security / auditing staff Human factors experts Documentation specialists
Analyst as a Member of System Development TeamComment on / think about:What differentiates high performing
teams from less successful ones?
What Goes Wrong in General when Applying Skills in an Organization?12. Too long
11. Inability to change business processes10. Not allowing out-dated system components to be replaced 9. Excessive spending on “maintenance” 8. Functions delivered are out-of-date 7. Inadequate technology impedes rapid response to market 6. Users lose patience, but “home grown” solutions out-of-
control 5. Critical data locked inside inaccessible systems 4. IS development priorities not consistent with business
priorities 3. IS staff does not understand business or its needs 2. Management does not understand IS 1. IS unplanned or misdirected
Systems Development Methodology
A standard process followed in an organization to conduct all the steps necessary to analyze, design, implement, and maintain information systems
Methodology, Technique, Tool Methodology
– Overall approach, usually within a framework or architecture
Technique– A way to do a specific task (e.g., interview, ERD,
DFD, use-case diagram)– Often graphical
Tool– An aid which helps to complete a technique (e.g.,
Visio, PowerPoint, MS-Project) or manage data used across techniques
CASE: Examples of Tools
Case tools– Software tools that provide automated
support for some portion of the systems development process
Examples of tools/functions supported– Diagramming– Generating screens and reports
What Is Analyzed Via Methodology? Data (input/capture and storage) Information (output/presentation) Data flow (movement/transfer) Processing logic
(manipulation/analysis)
Note: These can be viewed as related but separate systems!
Types of Information Systems Transaction processing MIS Business Intelligence
– DSS (Individual & Group)– ESS/EIS– Expert System
Note: See Table 1-1 for differences– characteristics– development orientation (e.g., process or
data)
Traditional Systems Development Methodology: Systems Development Life Cycle (SDLC)
Chapters 4-5
Chapters 6-9
Chapters 10-14
Chapter 16
Chapter 15
SDLC Planning Phase
Identify, analyze, prioritize, and arrange IS needs
SDLC Analysis Phase
Study and structure system requirements
SDLC Design Phase
Convert recommended solution to system specifications
Logical design: functional features described independently of computer platform
Physical design: logical specifications transformed to technology-specific details
SDLC Implementation Phase
Code, test, install, and support the information system
SDLC Maintenance Phase
Systematically repair and improve the information system
Figure 1-12: Rapid Application Development
Iterative/Agile Development Repetition of refining steps Successively closer to goal Evolutionary/adaptive
– Continuous, self-adapting change– simpler state to more complex or
better state Focus on people not roles (people
are talented and creative, not replaceable parts) – see Table 1-4
Spiral Development
High-levelRequirements
Customer Review
DetailedRequirements
Analysis
Design
Figure 1-14: Phases of OOASD-Based Development
Figure 1-11: Prototyping: A Methodology or Component of Other Methodologies
How Do Methodologies Change? Some Trends Move from “art” -> “science”
(tension) In-house development Outsourcing Purchased applications Modularized Web orientation
In Summary
What is systems analysis and design?
What does a systems analyst do? What is a systems development
methodology?– Why use one?
Context Diagram of Data Flow Diagram (DFD)
E1: Customer
0Order
ProcessingSystem
E2: SupplierTentative Customer Order Tentative Material Order
Response to Tentative Material OrderResponse to Tentative Customer Order
E3: ProductDesignSystem
Materials Required
Data Input Screen