System Analysis

System AnalysisSystem Analysis

- Mr. Ahmad Al-Ghoul- Mr. Ahmad Al-Ghoul

System Analysis and System Analysis and DesignDesign

AvicennaAvicenna System Analysis and Design System Analysis and Design System Analysis System Analysis

22

learning Objectiveslearning Objectives Explain the Characteristics of a Explain the Characteristics of a

Good Analysis MethodGood Analysis Method Explain Explain Why Use a MethodologyWhy Use a Methodology Describe the three categorizes of Describe the three categorizes of

system development system development methodologiesmethodologies Process-centered MethodologiesProcess-centered Methodologies Data-centered MethodologiesData-centered Methodologies Object-oriented methodologiesObject-oriented methodologies

Explain Explain Waterfall Development, Parallel Waterfall Development, Parallel Development, Development, rapid application rapid application development (RAD)development (RAD)


33

IntroductionIntroductionThe process of system analysis and its planning The process of system analysis and its planning includes various stages. includes various stages. Over the years various methodologies have been Over the years various methodologies have been defined for this process.defined for this process. The methodologies themselves constitute a method The methodologies themselves constitute a method that regulates the various stages in the process ofthat regulates the various stages in the process ofplanning and developing the information system. planning and developing the information system. Each methodology has its own advantages and Each methodology has its own advantages and disadvantages but, generally, the correct disadvantages but, generally, the correct methodology must be adapted to the required methodology must be adapted to the required system.system.


44

IntroductionIntroduction

A methodology is a formalized approach to A methodology is a formalized approach to implementing the SDLC.implementing the SDLC.

Justified by experienceJustified by experience A methodology may or may not prescribe A methodology may or may not prescribe

a Life Cycle Model.a Life Cycle Model. The methodology will vary depending on The methodology will vary depending on

whether the emphasis is on businesses whether the emphasis is on businesses processes or on the data that supports the processes or on the data that supports the business.business.


55

Systems Development Systems Development MethodologiesMethodologies

Characteristics of a Good Analysis Characteristics of a Good Analysis MethodMethod Graphical with supporting text.Graphical with supporting text. Allow system to be viewed in a top-down and Allow system to be viewed in a top-down and

partitioned fashion.partitioned fashion. Minimum redundancies.Minimum redundancies. Reader should be able to predict system Reader should be able to predict system

behavior.behavior. Easy to understand by user.Easy to understand by user.


66


Why Use a Methodology?Why Use a Methodology? Distilled experience/best practiceDistilled experience/best practice Ensures user involvementEnsures user involvement Helps inexperienced analystsHelps inexperienced analysts Provides planning and controlProvides planning and control


77


Process-centered MethodologiesProcess-centered Methodologies This kind of methodologies focus on defining This kind of methodologies focus on defining

the activities associated with the system.the activities associated with the system. concentrate on representing the system concentrate on representing the system

concept as a set of processes with concept as a set of processes with information flowing into and out of the information flowing into and out of the processes.processes.


88


Data-centered MethodologiesData-centered Methodologies These methodologies focuses on defining the These methodologies focuses on defining the

content of the data storage containers and content of the data storage containers and how they are organized rather than the how they are organized rather than the activities which comes later.activities which comes later.

Data-centered methodologies utilize data Data-centered methodologies utilize data models as the core of understanding the models as the core of understanding the system concept, other models will be less system concept, other models will be less importantimportant..


99


Object-oriented methodologiesObject-oriented methodologies This methodology attempts to balance the This methodology attempts to balance the

focus between processes and data.focus between processes and data. Object-oriented methodology work well Object-oriented methodology work well

in situation in which complicated IS need in situation in which complicated IS need continues maintenance, adaptation and continues maintenance, adaptation and redesignredesign


1010


Waterfall DevelopmentWaterfall Development With waterfall development- based methodologies, the analysts With waterfall development- based methodologies, the analysts

and users proceed sequentially from one phase to the next.and users proceed sequentially from one phase to the next.

The advantages of waterfall development-based methodologies The advantages of waterfall development-based methodologies are:are:

The system requirements are identified long before The system requirements are identified long before programming begins.programming begins.

Changes to the requirements are minimized as the project Changes to the requirements are minimized as the project proceeds.proceeds.

Good for project managementGood for project management Results in solid, well-constructed systemsResults in solid, well-constructed systems


1111


The disadvantages of waterfall development-The disadvantages of waterfall development-based methodologies are:based methodologies are: The design must be completely specified before The design must be completely specified before

programming begins.programming begins. A long time elapses between the completion of the A long time elapses between the completion of the

system proposal in the analysis phase and the system proposal in the analysis phase and the delivery of the system.delivery of the system.

Difficult (expensive) to accommodate Difficult (expensive) to accommodate change after process is underway change after process is underway


1212

Systems Development Systems Development Methodologies [3]Methodologies [3]

Waterfall DevelopmentWaterfall Development


1313


Parallel DevelopmentParallel Development This methodology attempts to address the This methodology attempts to address the

long time interval between the analysis phase long time interval between the analysis phase and the delivery of the system.and the delivery of the system.


1414

Systems Development Systems Development Methodologies [3]Methodologies [3]


1515


Rapid Application Development (RAD)Rapid Application Development (RAD) RAD-based methodologies adjust the SDLC RAD-based methodologies adjust the SDLC

phases to get some part of system developed phases to get some part of system developed quickly and into the hands of the users.quickly and into the hands of the users.

Most RAD-based methodologies recommend Most RAD-based methodologies recommend that analysts use special techniques and that analysts use special techniques and computer tools to speed up the analysis, computer tools to speed up the analysis, design, and implementation phases, such as design, and implementation phases, such as CASE (computer-aided software engineering) CASE (computer-aided software engineering) tools.tools.


1616


Rapid Application Development (RAD)Rapid Application Development (RAD) Five key factorsFive key factors

1.1. Extensive user involvementExtensive user involvement2.2. Joint Application Design sessionsJoint Application Design sessions3.3. PrototypingPrototyping4.4. Integrated CASE toolsIntegrated CASE tools5.5. Code generatorsCode generators


1717


Rapid Application Development (RAD)Rapid Application Development (RAD) RAD is a general strategy rather than a single RAD is a general strategy rather than a single

methodologymethodology GoalsGoals

To analyze a business process rapidlyTo analyze a business process rapidly To design a viable system solution through intense To design a viable system solution through intense

cooperation between users and developerscooperation between users and developers To get the finished application into the hands of the To get the finished application into the hands of the

users quicklyusers quickly Traditional SDLC steps are followed, but phases Traditional SDLC steps are followed, but phases

are combinedare combined Iteration is limited to design and development Iteration is limited to design and development

phasesphases


1818

Systems Development Methodologies (Systems Development Methodologies (RAD) [2]RAD) [2]AdvantagesAdvantages DisadvantagesDisadvantagesDramatic time savings the Dramatic time savings the systems development effortsystems development effort

More speed and lower cost may More speed and lower cost may lead to lower overall system lead to lower overall system qualityquality

Can save time, money and Can save time, money and human efforthuman effort

Danger of misalignment of Danger of misalignment of system developed via RAD with system developed via RAD with the business due to missing the business due to missing information information

Tighter fit between user Tighter fit between user requirements and system requirements and system specificationsspecifications

May have inconsistent internal May have inconsistent internal designs within and across designs within and across systemssystems

Works especially well where Works especially well where speed of development is speed of development is importantimportant

Possible violation of programming Possible violation of programming standards related to inconsistent standards related to inconsistent naming conventions and naming conventions and inconsistent documentationinconsistent documentation

Ability to rapidly change system Ability to rapidly change system design as demanded by usersdesign as demanded by users

Difficulty with module reuse for Difficulty with module reuse for future systemsfuture systems

System optimized for users System optimized for users involved in RAD processinvolved in RAD process

Lack of scalability designed into Lack of scalability designed into systemsystem

Concentrates on essential system Concentrates on essential system elements from user viewpointelements from user viewpoint

Lack of attention to later systems Lack of attention to later systems administration built into systemadministration built into system

Strong user stake and ownership Strong user stake and ownership of systemof system

High cost of commitment on the High cost of commitment on the part of key user personnelpart of key user personnel


1919

Sequence SummarySequence Summary A methodology is a formalized approach to implementing A methodology is a formalized approach to implementing

the SDLC.the SDLC. Process centered methodologies, the focus is on Process centered methodologies, the focus is on

defining the activities associated with the system.defining the activities associated with the system. Data centered methodologies focuses on defining the Data centered methodologies focuses on defining the

content of the data storage containers and how they are content of the data storage containers and how they are organized.organized.

Object-oriented methodology attempts to balance the Object-oriented methodology attempts to balance the focus between processes and data.focus between processes and data.

waterfall development- based methodologies, the waterfall development- based methodologies, the analysts and users proceed sequentially from one phase analysts and users proceed sequentially from one phase to the next.to the next.

Rapid application development (RAD) resembles a Rapid application development (RAD) resembles a condensed version of the entire SDLC, with users condensed version of the entire SDLC, with users involved every step of the wayinvolved every step of the way


2020

Sequence SummarySequence Summary In this Sequence we haveIn this Sequence we have

Defined the term development methodologyDefined the term development methodology Explained the Characteristics of a Good Explained the Characteristics of a Good

Analysis MethodAnalysis Method Explained Explained Why Use a MethodologyWhy Use a Methodology Described the three categorizes of system Described the three categorizes of system

development methodologiesdevelopment methodologies Process-centered MethodologiesProcess-centered Methodologies Data-centered MethodologiesData-centered Methodologies Object-oriented methodologiesObject-oriented methodologies

Explained Explained Waterfall Development, Parallel Waterfall Development, Parallel Development, and Development, and rapid application development rapid application development (RAD).(RAD).


2121

ReferenceReference

[1] System Analysis and Design, Sixth Edition[1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Authors: Gary B. Shelly, Thomas J. Cashman and Harry J.

Rosenblatt Rosenblatt Publisher: SHELLY CASHMAN SEWIES.Publisher: SHELLY CASHMAN SEWIES.

[2] Modern Systems Analysis and Design Third Edition[2] Modern Systems Analysis and Design Third Edition Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S.

ValacichValacich Publisher: prentice hall Publisher: prentice hall

[3] System Analysis and Design, 3[3] System Analysis and Design, 3rdrd Edition Edition Authors: Dennis, Wixom, & RothAuthors: Dennis, Wixom, & Roth Publisher: John Wiley & sonsPublisher: John Wiley & sons

Date post:	25-Feb-2016
Category:	Documents
Upload:	annona
View:	93 times
Download:	5 times

System Analysis

Documents