introduction to system analysis and design - dr. mahmoud abu-arra - dr. mahmoud abu-arra - mr. ahmad...

Introduction to System Introduction to System Analysis and DesignAnalysis and Design

- Dr. Mahmoud Abu-Arra- Dr. Mahmoud Abu-Arra

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

System Analysis and System Analysis and DesignDesign

AvicennaAvicenna System Analysis and Design IntroSystem Analysis and Design Introduction to SADduction to SAD

22

Learning ObjectivesLearning Objectives Explain systems development tools, Explain systems development tools,

including modeling, prototyping, and including modeling, prototyping, and CASE toolsCASE tools

Discuss and distinguish between system Discuss and distinguish between system development methodologiesdevelopment methodologies

Explain systems development methods, Explain systems development methods, RAD, JADRAD, JAD

Distinguish between structured analysis Distinguish between structured analysis and object-oriented methodologyand object-oriented methodology

Discuss how to use appropriate system Discuss how to use appropriate system development methoddevelopment method


33

IntroductionIntroduction There are several tools and techniques There are several tools and techniques

to build information systems, to choose to build information systems, to choose the appropriate one to build your the appropriate one to build your system, you must study them first and system, you must study them first and knows their uses.knows their uses.

Methodology is an approach, a method Methodology is an approach, a method or a technique for developing or a technique for developing information systems. The methodology information systems. The methodology defines a method and a way of defines a method and a way of developing an information system, developing an information system, guiding planners in the desired working guiding planners in the desired working method.method.


44

Systems Development Tools Systems Development Tools and Techniquesand Techniques

Systems analysts must know how to use a Systems analysts must know how to use a variety of techniques such as modeling, variety of techniques such as modeling, prototyping, and computer-aided systems prototyping, and computer-aided systems engineering tools to plan, design, and engineering tools to plan, design, and implement information systems.implement information systems.

Systems analysts work with these tools in Systems analysts work with these tools in a team environment, where input from a team environment, where input from users, managers, and IT staff contributes users, managers, and IT staff contributes to the system design.to the system design.


55

Systems Development Tools and Systems Development Tools and TechniquesTechniques

ModelingModeling Modeling produces a graphical representation of a concept Modeling produces a graphical representation of a concept

or process that system developers can analyze, test, and or process that system developers can analyze, test, and modify. Modeling Used to describe and simplify an modify. Modeling Used to describe and simplify an information system:information system:

Business model or Requirements modelBusiness model or Requirements model Describes the information that a system must provide.Describes the information that a system must provide.

Data modelData model Describes the data structure and design.Describes the data structure and design.

Object modelObject model Describes objects, which combine data and processes.Describes objects, which combine data and processes.

Network modelNetwork model Describes the design and protocols of telecommunication Describes the design and protocols of telecommunication

linkslinks Process modelProcess model

Describes the logic that programmers use to write code Describes the logic that programmers use to write code modulesmodules

Modeling techniques, including data flow diagrams Modeling techniques, including data flow diagrams and entity relationship diagrams, and unified and entity relationship diagrams, and unified modeling language diagrams.modeling language diagrams.


66


ProsPros Speeds up the Speeds up the

development process development process significantlysignificantly

Users interact with Users interact with Prototype very quicklyPrototype very quickly

Users can identify needed Users can identify needed changes and refine real changes and refine real requirementsrequirements

ConsCons Important decisions might Important decisions might

be made too early, before be made too early, before business or IT issues are business or IT issues are thoroughly understoodthoroughly understood

Initial Design decisions Initial Design decisions may be poormay be poor

PrototypingPrototypingPrototyping tests system concepts and provide an Prototyping tests system concepts and provide an opportunity to examine input, output, and user opportunity to examine input, output, and user interface before final decisions are made.interface before final decisions are made.Early working version of an information systemEarly working version of an information system


77


Computer-Aided Systems Computer-Aided Systems Engineering (CASE) ToolsEngineering (CASE) Tools Also called computer-aided software Also called computer-aided software

engineering, is a technique that uses engineering, is a technique that uses powerful software, called CASE tools, to powerful software, called CASE tools, to help systems analysts develop and help systems analysts develop and maintain information systems.maintain information systems.

Framework for systems development Framework for systems development and support a wide variety of design and support a wide variety of design methodologiesmethodologies


88

Methodologies in the development Methodologies in the development of information systemsof information systems

Bottom upBottom up A formalized approach to implementing the SDLCA formalized approach to implementing the SDLC

A series of steps and deliverablesA series of steps and deliverables As the base for the information system, this As the base for the information system, this

approach uses the organization’s operational approach uses the organization’s operational level.level.

The starting point is that, the operational level The starting point is that, the operational level constitutes the core of the organization.constitutes the core of the organization.

The information requirements of the intermediate The information requirements of the intermediate and management levels will be supplied by the and management levels will be supplied by the various processing stages of operational level various processing stages of operational level data.data.

Using this approach, studying the needs and Using this approach, studying the needs and planning of the future system will be prepared planning of the future system will be prepared initially for the operational level.initially for the operational level.


99


Top DownTop DownThis approach uses the organization’s This approach uses the organization’s management level as the base for the management level as the base for the information system. The definition of its information system. The definition of its requirements and the system goals are requirements and the system goals are dictated by the organization’s management.dictated by the organization’s management.


1010


Integrated ApproachIntegrated Approach This approach combines both methods, with This approach combines both methods, with

the aim of benefiting from both the Bottom Up the aim of benefiting from both the Bottom Up and the Top Down approaches.and the Top Down approaches.

With this approach, the initial planning is With this approach, the initial planning is carried out by the Top Down methodcarried out by the Top Down method

The planning of the systems themselves (sub-The planning of the systems themselves (sub-systems) is performed using the Bottom Up systems) is performed using the Bottom Up approach in order to ensure proper planning, approach in order to ensure proper planning, based on operational level requirements.based on operational level requirements.


1111

Methodologies in the development of Methodologies in the development of information systemsinformation systems

Structured AnalysisStructured Analysis ““Structured analysis is a set of techniques and graphical Structured analysis is a set of techniques and graphical

tools that allow the analyst to develop a new kind of system tools that allow the analyst to develop a new kind of system specification that are easily understandable to the user. specification that are easily understandable to the user. Analysts work primarily with their wits, pencil and paper.” Analysts work primarily with their wits, pencil and paper.” [Kendall 1996][Kendall 1996]

Uses a set of process models to describe a system Uses a set of process models to describe a system graphicallygraphically

The availability of CASE tools in the 1990s enabled analysts The availability of CASE tools in the 1990s enabled analysts to develop and modify the graphical SASD models.to develop and modify the graphical SASD models.

[1]


1212


Object-oriented (O-O) analysisObject-oriented (O-O) analysis O-O analysis combines data & processes into O-O analysis combines data & processes into

things called objectsthings called objects O-O analysis uses object models to represent O-O analysis uses object models to represent

data and behavior, and to show how objects data and behavior, and to show how objects affect other objectsaffect other objects

By describing the objects (data) and methods By describing the objects (data) and methods (processes) needed to support business (processes) needed to support business operation, a system developer can design operation, a system developer can design reusable components that allow faster system reusable components that allow faster system implementation and decreased development implementation and decreased development costcost


1313


Object-oriented (O-O) analysisObject-oriented (O-O) analysis objects objects combine data and processes. Object are the end combine data and processes. Object are the end

product of object-oriented analysis. Object is a member product of object-oriented analysis. Object is a member of a classof a class

Class Class is a collection of similar objectsis a collection of similar objects Objects possess characteristics called propertiesObjects possess characteristics called properties Properties inherits from the object class or possesses on Properties inherits from the object class or possesses on

its ownits own In O-O design, built-in processes called methods can In O-O design, built-in processes called methods can

change an object’s propertieschange an object’s properties Object can send information to anther object by using a Object can send information to anther object by using a

messagemessage A message requests specific behavior or information A message requests specific behavior or information

from another objectfrom another object


1414


The PERSON class includes INSTRUCTOR and STUDENT objects, which have their own properties and inherited properties.

Object-oriented (O-O) analysisObject-oriented (O-O) analysis

[1]


1515


Joint Application Development and Rapid Joint Application Development and Rapid Application DevelopmentApplication Development JAD JAD – The basic idea behind JAD is to bring structure – The basic idea behind JAD is to bring structure

to the requirements determination phase of analysis to the requirements determination phase of analysis and to the reviews that occur as a part of design.and to the reviews that occur as a part of design.

Team based fact findingTeam based fact finding Users, Managers and Analysts work together for Users, Managers and Analysts work together for

several daysseveral days System requirements are reviewedSystem requirements are reviewed Structured meetingsStructured meetings


1616


RADRAD – created to radically decrease the time – created to radically decrease the time needed to design and implement information needed to design and implement information systems.systems.

RAD relies on extensive user involvement.RAD relies on extensive user involvement. Incorporate special techniques and tools:Incorporate special techniques and tools:

CASE toolsCASE tools JAD sessionsJAD sessions Fourth generation/visualization programming Fourth generation/visualization programming

languageslanguages Code generatorsCode generators


1717


There are many other There are many other methods methods

A systems analyst should A systems analyst should understand the alternative understand the alternative methodologies and their methodologies and their individual strengths and individual strengths and weaknesses.weaknesses.

how you will choose the how you will choose the suitable method?suitable method?

Selecting a methodology is Selecting a methodology is not simple, as no one not simple, as no one methodology is always best.methodology is always best.

Many organizations have their Many organizations have their own standards.own standards.

We will discuss this topic in We will discuss this topic in more detail in the analysis more detail in the analysis chapterchapter


1818

Sequence SummarySequence Summary

In this Sequence we haveIn this Sequence we have Discussed the various systems Discussed the various systems

development methods, tools, and development methods, tools, and techniquestechniques

Distinguished between structured Distinguished between structured analysis and object-oriented analysis and object-oriented methodologymethodology

Discussed how to use appropriate Discussed how to use appropriate system development methodsystem development method


1919

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. Rosenblatt , Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. 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. ValacichAuthors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich Publisher: prentice hall Publisher: prentice hall

[3] System Analysis and Design, 3[3] System Analysis and Design, 3rdrd Edition EditionAuthors: Dennis, Wixom, & RothAuthors: Dennis, Wixom, & RothPublisher: John Wiley & sonsPublisher: John Wiley & sons

introduction to system analysis and design - dr. mahmoud abu-arra - dr. mahmoud abu-arra - mr. ahmad...

Documents