Systems analysis and design in a changing world 6th edition

An Overview of Systems Analysis and Design

Chapter 10

SBM4201 System Analysis and Design

Bahareh Berenjforoush

Bahareh.azar@apicollege.edu.au

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Systems Analysis and Design in a Changing World, 6th and 7th Edition

Objectives

Software Development and Systems Analysis and Design

Systems Development Lifecycle (SDLC)

Approaches to System Development

The SDLC Support Phase

Methodologies, Models, Tools, and Techniques

Approaches to Software Construction and Modeling

Agile Development

Systems Analysis and Design in a Changing World, 6th and 7th Edition

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Software Development

Computer application (app) – a computer software program that executes on a computing device to carry out a specific set of functions

Modest scope

Information system – a set of interrelated components that collects, processes, stores, and provides as output the information needed to complete business tasks

Broader in scope than “app”

Includes database and related manual processes

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Systems Analysis and Design in a Changing World, 7th Edition

Software Development

Systems analysis – those activities that enable a person to understand and specify what an information system should accomplish

Systems design – those activities that enable a person to define and describe in detail the system that solves the need

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Software Development

Understand the need (business need)

Capture the vision

Define a solution

Communicate the vision and solution

Build the solution

Confirm that the solution meets the need

Launch the solution system

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System Development Life Cycle (SDLC)

The process consisting of all activities required to build, launch, and maintain an information system. Six core processes are:

Identify the problem or need and obtain approval

Plan and monitor the project

Discover and understand the details of the problem or need

Design the system components that solve the problem

Build, test, and integrate system components

Complete system tests and then deploy the solution

Systems Analysis and Design in a Changing World, 7th Edition

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Iterative and Agile Systems Development Lifecycle (SDLC)

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The System Development Life Cycle (SDLC)

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There are two general approaches to the SDLC

Predictive Approach

Waterfall model

Assumes the project can be planned in advance and that the information system can be developed according to the plan

Requirements are well understood and/or low technical risk

Adaptive Approach to the SDLC

Iterative model (as see in this text)

Assumes the project must be more flexible and adapt to changing needs as the project progresses

Requirements and needs are uncertain and/or high technical risk

Systems Analysis and Design in a Changing World, 6th Edition

The System Development Life Cycle (SDLC)

Most projects fall on a continuum between Predictive and Adaptive

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Systems Analysis and Design in a Changing World, 6th Edition

Traditional Predictive SDLC

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Earlier approach based on engineering

Typically have sequential Phases

Phases are related groups of development activities, such as planning, analysis, design, implementation, and deployment

Waterfall model

SDLC that assumes phases can be completed sequentially with no overlap or iteration

Once one phase is completed, you fall over the waterfall to the next phase, no going back

Systems Analysis and Design in a Changing World, 6th Edition

Traditional Predictive SDLC

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Systems Analysis and Design in a Changing World, 6th Edition

Newer Overlapping Phases Predictive SDLC

More flexibility, but still assumes predictive planning and sequential phases

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Systems Analysis and Design in a Changing World, 6th Edition

Newer Adaptive SDLC

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Emerged in response to increasingly complex requirements and uncertain technological environments

Always includes iterations where some of design and implementation is done from the beginning

Many developers claim it is the only way to develop information systems

Many IS managers are still sceptical

Systems Analysis and Design in a Changing World, 6th Edition

Iterative Model

Popular Way to Represent Adaptive SDLC

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Systems Analysis and Design in a Changing World, 6th Edition

Iterative development -- an approach to system development in which the system is “grown” piece by piece through multiple iterations

Complete small part of system (mini-project), then repeat processes to refine and add more, then repeat to refine and add more, until done

Core Processes vs. Iterations Model

The Adaptive SDLC used in this Text

Shows core processes, not phases, plus iterations in a sequence for management checkpoints

Based on the Unified Process SDLC (see chapter 14)

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Systems Analysis and Design in a Changing World, 6th Edition

The SDLC Support Phase

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All information systems need to be supported once completed

Predictive SDLCs typically include support as a project phase

Adaptive SDLCs treat support as a separate project

Support Activities

Activities whose objective is to maintain and enhance the system after it is installed and in use

Systems Analysis and Design in a Changing World, 6th Edition

Support Activities

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Maintaining the system

Fix problems/error

Make minor adjustments

Update for changes in operating systems or environments

Enhancing the system

Add desired functionality

Add or change functionality to comply with regulations or legislation

Supporting the users

Ongoing user training

Help desk

Systems Analysis and Design in a Changing World, 6th Edition

Methodologies, Models, Tools, and Techniques

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Methodologies

Provides guidelines for every facet of system development: What to do when, why and how

Specifies an SDLC with activities and tasks

Specifies project planning and project management models and reporting

Specifies analysis and design models to create

Specifies implementation and testing techniques

Specifies deployment and support techniques

Other term used is System Development Process

Systems Analysis and Design in a Changing World, 6th Edition

Methodologies, Models, Tools, and Techniques

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Model

An abstraction of an important aspect of the real world.

Makes it possible to understand a complex

concept by focusing only on a relevant part

Each model shows a different aspect of the concept

Crucial for communicating project information

In IS, some models are of system components

Some models are used to manage the development process

Systems Analysis and Design in a Changing World, 6th Edition

Methodologies, Models, Tools, and Techniques

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Systems Analysis and Design in a Changing World, 6th Edition

Methodologies, Models, Tools, and Techniques

Tools

Software applications that assists developers in creating models or other components required for a project

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Systems Analysis and Design in a Changing World, 6th Edition

Methodologies, Models, Tools, and Techniques

Technique

A collection of guidelines that help an analyst complete an activity or task

Learning techniques is the key to having expertise in a field

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Systems Analysis and Design in a Changing World, 6th Edition

Methodologies, Models, Tools, and Techniques

A Methodology includes a collection of techniques that are used to complete activities and tasks, including modeling, for every aspect of the project

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Systems Analysis and Design in a Changing World, 6th Edition

Two Approaches to Software Construction and Modeling

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The Structured Approach

Earlier approach Assumes a system is a collection of processes that interact with data

Structured analysis, structured design, and structured programming

The Object-Oriented Approach

More recent approach. Assumes a system is a collection of objects that interact to complete tasks

OO analysis, OO design, and OO programming

Systems Analysis and Design in a Changing World, 6th Edition

The Structured Approach

Entity-relationship diagram

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Systems Analysis and Design in a Changing World, 6th Edition

The Structured Approach

How it fits together

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Systems Analysis and Design in a Changing World, 6th Edition

The Object-Oriented Approach

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Object-oriented analysis (OOA)

The process of identifying and defining the use cases and sets of objects (classes) in the new system

Object-oriented design (OOD)

Defining all of the types of objects necessary to communicate with people and devices and showing how they interact to complete tasks

Object-oriented programming (OOP)

Writing statements that define the actual classes and what each object of the class does

Systems Analysis and Design in a Changing World, 6th Edition

The Object-Oriented Approach

UML Design Class Diagram

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Systems Analysis and Design in a Changing World, 6th Edition

Agile Development

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A guiding philosophy and set of guidelines for developing information systems in an unknown, rapidly changing environment

Complements Adaptive SDLCs and Methodologies that support it

Takes adaptive and makes sure developers are fast on their feet to respond to changes

Systems Analysis and Design in a Changing World, 6th Edition

Agile Development Philosophies and Values

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This text emphasizes agile values, as stated by the “Manifesto for Agile Development”

Value responding to change over following a plan

Value individuals and interactions over processes and tools

Value working software over comprehensive documentation

Value customer collaboration over contract negotiation

Systems Analysis and Design in a Changing World, 6th Edition

Summary

This lecture is about developing information systems that solve an organization need

System development involves 6 core processes, known as the SDLC

There are two approaches to the SDLC: Predictive and Adaptive

A predictive SDLC, also known as the waterfall model, is used when it is possible to plan the project completely in advance

An Adaptive SDLC, which uses iteration, is used when the requirements are less certain and the project will need to react to changes

This text uses an adaptive approach to the SDLC

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Systems Analysis and Design in a Changing World, 6th and 7th Edition

Summary (continued)

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All new information systems require support once completed

System development project use a methodology (or development process) and many are available. A methodology includes an SDLC and tools, techniques, and models

There are two approaches to construction and modeling software: the traditional structured approach and the newer object- oriented approach

Agile development is the current trend in system development

Systems Analysis and Design in a Changing World, 6th and 7th Edition

References

Satzinger .J, Jackson. R & Burd. S, 2012, Systems Analysis and Design in a Changing 6th edn, Cengage, Australia.

Satzinger .J, Jackson. R & Burd. S, 2016, Systems Analysis and Design in a Changing 7th edn, Cengage, Australia.