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Methodologies of SDLC

Lecture 5

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• Methodologies of the SDLC

• Traditional Approach to SDLC

• Object-Oriented Approach to SDLC

• CASE Tools

Lecturer details

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Methodology• Comprehensive guidelines to follow for completing every SDLC activity• Collection of models, tools, and techniques

What is Methodology

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ModelsRepresentation of an important aspect of real world, but not same as real thing• physical (like a model of an airplane)• abstract (e.g. in form of mathematical notation)

What is a model

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Tools• Software support that helps create models or other required project components • Range from simple drawing programs to complex CASE tools to project management software

What are Tools

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Techniques• Collection of guidelines that help analysts complete a system development activity or task• Can be step-by-step instructions or just general advice

What are Techniques

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Traditional approach (1)• Also called structured system development• Structured analysis and design technique (SADT)

Object-oriented approach (2)• Also called OOA, OOD, and OOP• Views information system as collection of interacting objects that work together to accomplish tasks.

Two approaches to system development

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Structured Analysis• Define data, system needs to store and use (data requirements)• Define inputs and outputs• Define how functions work together to accomplish tasks• Data flow diagrams (DFD) and entity relationship diagrams (ERD) show results of structured analysis

Traditional approach (1)

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Technique developed to provide design guidelines • What set of programs should be• What program should accomplish• How programs should be organized into a hierarchy• Modules are shown with structure chart

Traditional approach (1)

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Structured programming• Improves computer program quality• Allows other programmers to easily read and modify code• Each program module has one beginning and one ending• Three programming constructs (sequence, decision, repetition)

Traditional approach (1)

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Stages overview

Traditional approach (1)

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• Views information system as collection of interacting objects that work together to accomplish tasks• Objects – things in computer system that can respond to messages• OO languages: Java, C++, C#, .NET

Object-oriented approach (2)

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Object-oriented approach (2)

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Object-oriented analysis (OOA)• Defines types of objects users deal with• Shows use cases that are required to complete tasks

Object-oriented design (OOD)• Defines object types needed to communicate with people and devices in system• Shows how objects interact to complete tasks• Refines each type of object for implementation with specific language of environment

Object-oriented programming (OOP) Writing statements in programming language to define what each type of object does •.NET, VB, Java

Object-oriented approach (2)

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Class diagram made during OOA

Object-oriented approach (2)

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• CASE tools are software tools designed to help systems analyst complete development tasks

Computer Aided System Engineering(CASE) tools

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End

Thank you

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