modern systems analysis and design_ch01

8/14/2019 Modern Systems Analysis and Design_CH01

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2Chapter 1

Learning Objectives

Define information systems analysis and design.

Describe the different types of information systems.

Describe the information Systems Development LifeCycle (SDLC).

Explain Rapid Application Development (RAD),prototyping, Joint Application Development (JAD), andComputer Aided Software Engineering (CASE).

Describe agile methodologies and eXtremeprogramming.

Explain Object Oriented Analysis and Design and theRational Unified Process (RUP).


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5Chapter 1

A Modern Approach to Systems

Analysis and Designn1950s: focus on efficient automation of

existing processes

n1960s: advent of 3GL, faster and morereliable computers

n1970s: system development becomesmore like an engineering discipline


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Analysis and Design (Cont.)n1980s: major breakthrough with 4GL,

CASE tools, object oriented methods

n1990s: focus on system integration, GUIapplications, client/server platforms,Internet

nThe new century: Web application

development, wireless PDAs, component-based applications


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7Chapter 1


Analysis and Design (Cont.)nApplication Software

Computer software designed to support

organizational functions or processes.

nSystems Analyst

Organizational role most responsible for

analysis and design of information systems.


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8Chapter 1


Analysis and Design (Cont.)


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Types of Information Systems

and Systems DevelopmentnTransaction Processing Systems (TPS)

Automate handling of data about business

activities (transactions)Process orientation

nManagement Information Systems (MIS)

Converts raw data from transactionprocessing system into meaningful form

Data orientation


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Types of Information Systems

and Systems Development (Cont.)nDecision Support Systems (DSS)

Designed to help decision makers

Provides interactive environment for decisionmaking

Involves data warehouses, executive

information systems (EIS)

Database, model base, user dialogue


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11Chapter 1

Summary of Information

Systems Types


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12Chapter 1

Developing Information Systems

nSystem Development Methodology is a

standard process followed in an

organization to conduct all the stepsnecessary to analyze, design, implement,

and maintain information systems.


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Systems Development Life

Cycle (SDLC)n Traditional methodology used to develop,

maintain, and replace information systems.

n Phases in SDLC:Planning

Analysis

Design

Implementation

Maintenance


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14Chapter 1

Standard and Evolutionary Views

of SDLC


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Systems Development Life Cycle

(SDLC) (Cont.)nPlanning an organizations total

information system needs are identified,

analyzed, prioritized, and arranged.nAnalysis system requirements are

studied and structured.


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(SDLC) (Cont.)nDesign a description of the

recommended solution is converted into

logical and then physical systemspecifications.

nLogical design all functional features ofthe system chosen for development in

analysis are described independently ofany computer platform.


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(SDLC) (Cont.)nPhysical design the logical

specifications of the system from logical

design are transformed into thetechnology-specific details from which all

programming and system construction can

be accomplished.


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(SDLC) (Cont.)nImplementation the information system

is coded, tested, installed and supported in

the organization.nMaintenance an information system is

systematically repaired and improved.


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20Chapter 1

The Heart of the Systems Development

Process

Current practice combines analysis, design, and implementation

into a single iterative and parallel process of activities


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Traditional Waterfall SDLC

One phase begins

when anothercompletes, little

backtracking and

looping


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Problems with Waterfall Approach

nSystem requirements locked in after

being determined (can't change).

nLimited user involvement (only inrequirements phase).

nToo much focus on milestone deadlines of

SDLC phases to the detriment of sounddevelopment practices.


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23Chapter 1

Different Approaches to Improving

DevelopmentnPrototyping

nComputer-Aided Software

Engineering (CASE) Tools

nJoint Application Design (JAD)


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24Chapter 1

Different Approaches to Improving

Development (Cont.)nRapid Application Development

(RAD)

nAgile Methodologies

neXtreme Programming


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Prototyping

nIterative development process:

nRequirements quickly converted to a

working system.

nSystem is continually revised.

nClose collaboration between users and

analysts.


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26Chapter 1

Prototyping (Cont.)


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Computer-Aided Software

Engineering (CASE) ToolsnDiagramming tools enable graphical

representation.

nComputer displays and report generatorshelp prototype how systems look andfeel.


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Engineering (CASE) Tools (Cont.)nAnalysis tools automatically check for

consistency in diagrams, forms, andreports.

nCentral repository for integrated storage ofdiagrams, reports, and projectmanagement specifications.


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Engineering (CASE) Tools (Cont.)nDocumentation generators standardize

technical and user documentation.

nCode generators enable automaticgeneration of programs and databasecode directly from design documents,diagrams, forms, and reports.


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CASE Tools (Cont.)

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Joint Application Design (JAD)

nStructured process involving users,

analysts, and managers.

nSeveral-day intensive workgroup sessions.nPurpose: to specify or review system

requirements.


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Rapid Application Development

(RAD)nMethodology to radically decrease

design and implementation time.

nInvolves: extensive user involvement,

prototyping, JAD sessions, integrated

CASE tools, and code generators.


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34Chapter 1

Rapid Application Development

(RAD) (Cont.)


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Agile Methodologies

nMotivated by recognition of software

development as fluid, unpredictable, and

dynamic.nThree key principles

Adaptive rather than predictive.

Emphasize people rather than roles.Self-adaptive processes.


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Agile Methodologies (Cont.)

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eXtreme Programming

nShort, incremental development cycles.

nAutomated tests.

nTwo-person programming teams.


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eXtreme Programming (Cont.)

nCoding and testing operate together.

nAdvantages:

Communication between developers.

High level of productivity.

High-quality code.


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39Chapter 1

Object-Oriented Analysis and

Design (OOAD)

nBased on objects rather than data orprocesses.

nObject: a structure encapsulatingattributes and behaviors of a real-world entity.

O O


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Object-Oriented Analysis and

Design (OOAD) (Cont.)

nObject class: a logical grouping ofobjects sharing the same attributes

and behaviors.nInheritance: hierarchical

arrangement of classes enable

subclasses to inherit properties ofsuperclasses.


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41Chapter 1

Rational Unified Process (RUP)

nAn object-oriented systems development

methodology.

nRUP establishes four phase ofdevelopment: inception, elaboration,

construction, and transition.

nEach phase is organized into a number ofseparate iterations.


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O A h t S t


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43Chapter 1

Our Approach to Systems

Development

nThe SDLC is an organizing and guiding

principle in this book.

nWe may construct artificial boundaries orartificially separate activities and

processes for learning purposes.

nOur intent is to help you understand all thepieces and how to assemble them.


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44Chapter 1

Summary

nIn this chapter you learned how to:

Define information systems analysis and

design.

Describe the different types of informationsystems.

Describe the information Systems

Development Life Cycle (SDLC).


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45Chapter 1

Summary (Cont.)

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).

modern systems analysis and design_ch01

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