Chapter Extension 19

Alternative Development Techniques

© 2008 Pearson Prentice Hall, Experiencing MIS, David Kroenke

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Study Questions

Why is rapid application development rapid? What is object-oriented development? What are the phases and principles of the

unified process? What is extreme about extreme

programming? How do development techniques compare?

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Why Is Rapid Development Rapid?

RAD– Five phases:

Requirements, design, implementation, conversion,maintenance

– Design/implement/fix Breaks up design and implementation phases into smaller

chunks Uses computer assistance Incremental development

– Requirements less detailed because users actively involved

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Martin’s RAD Process

Figure CE19-1

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Rapid Application Design (RAD)

Characteristics– Design/implement/fix development process– Continuous user involvement throughout– Extensive use of prototypes– Joint application design– Use of CASE tools

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Prototypes

Mock-up of aspect of system Vary in functionality and utility Some designed to be thrown away Help users evaluate requirements

– show actual data in context– Provide opportunity for users to test interfaces– Communication device between users and developers

Only a mock-up– May imply application is more complete than it actually is

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Joint Application Design (JAD)

Teams conduct design activities Incorporates feedback and testing earlier in

development process Design meeting of short duration

– Goal is to keep scope small – Design completed in short period

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Computer-Assisted Software/Systems Engineering

CASE tools– “Software” focuses on program development– “Systems” focuses on systems development– Uses computer systems for development– Have repository

Database containing documents, data, prototypes, code

– Many have code generators Programs that generate application code

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Visual Development Tools

Used in RAD projects Improve developer productivity Creates skeleton code Developers add features and functions

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What Is Object-Oriented Development?

OOD– Programs developed through object-oriented

programming (OOP) Discipline for designing and writing computer programs Easier and cheaper to fix and adapt Business applications will have to integrate with non-

OOP programs

Unified Modeling Language– Diagramming techniques that facilitate OOP

development

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What Are the Phases and Principles of the Unified Process?

UP– Designed for use with UML– Five phases

InceptionSimilar to SDLC definition phase

ElaborationDevelopers construct and test framework

and architectureResults in working systemIterations driven by use casesSecurity addressed during this phase

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Five Phases, continued

ConstructionDevelopers design, implement, and test

features and functions

Multiple iterations

Prepares system for deployment Transition

Similar to SDLC conversion phase Maintenance

Similar to SDLC maintenance phase

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Phases of the Unified Process

Figure CE 19-6

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UP Principles

Figure CE 19-8

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Sears Standardizes Development

Sears used a variety of different system development methodologies– Systems were inconsistent in quality and

timeliness

Sears created single, consistent, enterprise-wide development process– Backed by software development tools– Based on Rational Unified Process (RUP)

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Security and Systems Development

Only authorized users can take authorized actions– Decide how users will be authenticated

IS authentication can be performed by operating system or network or perform own authentication

– Determine users groups Permissions defined for groups instead of individuals Easier to change as a group than for each individual

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Security and Systems Development, continued

– List primary features and functions of system Direct result of systems design activity

– Determine restrictions and enforcement Allow users to attempt action and issue error message Disable features and functions that user cannot perform Only display actions that users are authorized to

perform

– Allocate permissions to user groups Computer programs cannot provide effective

controls by themselves

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What Is Extreme About Extreme Programming?

Extreme Programming (XP)– Emerging technique for developing computer

programs– Used for developing application programs– Extreme iterative development

Two-week development cycle Customer centric Just-in-time (JIT) design Paired programming

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How Do Development Techniques Compare?

SDLC and RAD address information systems– Used to develop organizational information

systems

OOD with UP and XP concerned with development of computer programs– Used by software development vendors

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Comparison of Development Techniques

Figure CE 19-9

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Active Review

Why is rapid application development rapid? What is object-oriented development? What are the phases and principles of the

unified process? What is extreme about extreme

programming? How do development techniques compare?