systems development environment chapter 1 modern systems analysis & design

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