Botswana Accountancy College Systems Development Lecture PDF

Botswana Accountancy College Computing & Information Systems Module: Systems Development Lecturer: MN : The Systems Development Environment Reference: Modern Systems Analysis and Design (6th Edition) BAC - Systems Developmen...

Botswana Accountancy College Computing & Information Systems Module: Systems Development Lecturer: MN : The Systems Development Environment Reference: Modern Systems Analysis and Design (6th Edition) BAC - Systems Development - Year 1- 2020 1  Learning Objectives ✓ Define information systems analysis and design. ✓ Describe the information Systems Development Life Cycle (SDLC). ✓ Explain Rapid Application Development (RAD), prototyping, Computer Aided Software Engineering (CASE), and Service-Oriented Architecture (SOA). ✓ Describe agile methodologies and eXtreme programming. ✓ Explain Object Oriented Analysis and Design and the Rational Unified Process (RUP). BAC - Systems Development - Year 1- 2020 2 Introduction ◼ Information Systems Analysis and Design  Complex organizational process  Used to develop and maintain computer- based information systems  Used by a team of business and systems professionals BAC - Systems Development - Year 1- 2020 3 Introduction (Cont.) FIGURE 1-1 An organizational approach to systems analysis and design is driven by methodologies, techniques, and tools BAC - Systems Development - Year 1- 2020 4 A Modern Approach to Systems Analysis and Design ◼ 1950s: focus on efficient automation of existing processes ◼ 1960s: advent of 3GL, faster and more reliable computers ◼ 1970s: system development becomes more like an engineering discipline BAC - Systems Development - Year 1- 2020 5 A Modern Approach to Systems Analysis and Design (Cont.) ◼ 1980s: major breakthrough with 4GL, CASE tools, object oriented methods ◼ 1990s: focus on system integration, GUI applications, client/server platforms, Internet ◼ The new century: Web application development, wireless PDAs, component- based applications BAC - Systems Development - Year 1- 2020 6 A Modern Approach to Systems Analysis and Design (Cont.) ◼ Application Software  Computer software designed to support organizational functions or processes ◼ Systems Analyst  Organizational role most responsible for analysis and design of information systems BAC - Systems Development - Year 1- 2020 7 Developing Information Systems ◼ System Development Methodology is a standard process followed in an organization to conduct all the steps necessary to analyze, design, implement, and maintain information systems. BAC - Systems Development - Year 1- 2020 8 Systems Development Life Cycle (SDLC) ◼ Traditional methodology used to develop, maintain, and replace information systems. ◼ Phases in SDLC:  Planning  Analysis  Design  Implementation  Maintenance BAC - Systems Development - Year 1- 2020 9 Standard and Evolutionary Views of SDLC FIGURE 1-3 Evolutionary model FIGURE 1-2 The systems development life cycle BAC - Systems Development - Year 1- 2020 10 Systems Development Life Cycle (SDLC) (Cont.) ◼ Planning – an organization’s total information system needs are identified, analyzed, prioritized, and arranged ◼ Analysis – system requirements are studied and structured BAC - Systems Development - Year 1- 2020 11 Systems Development Life Cycle (SDLC) (Cont.) ◼ Design – a description of the recommended solution is converted into logical and then physical system specifications ◼ Logical design – all functional features of the system chosen for development in analysis are described independently of any computer platform BAC - Systems Development - Year 1- 2020 12 Systems Development Life Cycle (SDLC) (Cont.) ◼ Physical design – the logical specifications of the system from logical design are transformed into the technology-specific details from which all programming and system construction can be accomplished BAC - Systems Development - Year 1- 2020 13 Systems Development Life Cycle (SDLC) (Cont.) ◼ Implementation – the information system is coded, tested, installed and supported in the organization ◼ Maintenance – an information system is systematically repaired and improved BAC - Systems Development - Year 1- 2020 14 BAC - Systems Development - Year 1- 2014 15 The Heart of the Systems Development Process FIGURE 1-7 The analysis–design–code–test loop Current practice combines analysis, design, and implementation into a single iterative and parallel process of activities. BAC - Systems Development - Year 1- 2014 16 Traditional Waterfall SDLC One phase begins when another completes, with little backtracking and looping. FIGURE 1-9 A traditional waterfall SDLC BAC - Systems Development - Year 1- 2014 17 Problems with Waterfall Approach ◼ System requirements “locked in” after being determined (can't change) ◼ Limited user involvement (only in requirements phase) ◼ Too much focus on milestone deadlines of SDLC phases to the detriment of sound development practices BAC - Systems Development - Year 1- 2014 18 Different Approaches to Improving Development ◼ CASE Tools ◼ Rapid Application Development (RAD) ◼ Agile Methodologies ◼ eXtreme Programming BAC - Systems Development - Year 1- 2014 19 Computer-Aided Software Engineering (CASE) Tools ◼ Diagramming tools enable graphical representation. ◼ Computer displays and report generators help prototype how systems “look and feel”. BAC - Systems Development - Year 1- 2014 20 Computer-Aided Software Engineering (CASE) Tools (Cont.) ◼ Analysis tools automatically check for consistency in diagrams, forms, and reports. ◼ A central repository provides integrated storage of diagrams, reports, and project management specifications. BAC - Systems Development - Year 1- 2014 21 Computer-Aided Software Engineering (CASE) Tools (Cont.) ◼ Documentation generators standardize technical and user documentation. ◼ Code generators enable automatic generation of programs and database code directly from design documents, diagrams, forms, and reports. BAC - Systems Development - Year 1- 2014 22 CASE Tools (Cont.) FIGURE 1-10 A class diagram from IBM’s Rational Rose (Source: IBM) BAC - Systems Development - Year 1- 2014 23 CASE Tools (Cont.) BAC - Systems Development - Year 1- 2014 24 Rapid Application Development (RAD) ◼ Methodology to radically decrease design and implementation time ◼ Involves: extensive user involvement, prototyping, JAD sessions, integrated CASE tools, and code generators BAC - Systems Development - Year 1- 2014 25 Rapid Application Development (RAD) (Cont.) FIGURE 1-11 RAD life cycle BAC - Systems Development - Year 1- 2014 26 Service-Oriented Architecture (SOA) ◼ An approach to systems development based on building complete systems through assembling software components, each of which model generic business functions BAC - Systems Development - Year 1- 2014 27 Service-Oriented Architecture (SOA) (Cont.) FIGURE 1-12 Illustration of a service, a credit check, used by applications and other services BAC - Systems Development - Year 1- 2014 28 Agile Methodologies ◼ Motivated by recognition of software development as fluid, unpredictable, and dynamic ◼ Three key principles  Adaptive rather than predictive  Emphasize people rather than roles  Self-adaptive processes BAC - Systems Development - Year 1- 2014 29 The Agile Methodologies group argues that software development methodologies adapted from engineering generally do not fit with real- world software development. BAC - Systems Development - Year 1- 2014 30 When to use Agile Methodologies ◼ If your project involves:  Unpredictable or dynamic requirements  Responsible and motivated developers  Customers who understand the process and will get involved BAC - Systems Development - Year 1- 2014 31 BAC - Systems Development - Year 1- 2014 32 eXtreme Programming ◼ Short, incremental development cycles ◼ Automated tests ◼ Two-person programming teams BAC - Systems Development - Year 1- 2014 33 eXtreme Programming (Cont.) ◼ Coding and testing operate together ◼ Advantages:  Communication between developers  High level of productivity  High-quality code BAC - Systems Development - Year 1- 2014 34 Object-Oriented Analysis and Design (OOAD) ◼ Based on objects rather than data or processes ◼ Object: a structure encapsulating attributes and behaviors of a real- world entity BAC - Systems Development - Year 1- 2014 35 Object-Oriented Analysis and Design (OOAD) (Cont.) ◼ Object class: a logical grouping of objects sharing the same attributes and behaviors ◼ Inheritance: hierarchical arrangement of classes enable subclasses to inherit properties of superclasses BAC - Systems Development - Year 1- 2014 36 Rational Unified Process (RUP) ◼ An object-oriented systems development methodology ◼ RUP establishes four phase of development: inception, elaboration, construction, and transition. ◼ Each phase is organized into a number of separate iterations. BAC - Systems Development - Year 1- 2014 37  FIGURE 1-13 Phases of OOSAD-based development BAC - Systems Development - Year 1- 2014 38 Our Approach to Systems Development ◼ The SDLC is an organizing and guiding principle in this book. ◼ We may construct artificial boundaries or artificially separate activities and processes for learning purposes. ◼ Our intent is to help you understand all the pieces and how to assemble them. BAC - Systems Development - Year 1- 2014 39 Summary ◼ In this chapter you learned how to: ✓ Define information systems analysis and design. ✓ Describe the information Systems Development Life Cycle (SDLC). ✓ Explain Rapid Application Development (RAD), prototyping, Computer Aided Software Engineering (CASE), and Service-Oriented Architecture (SOA). ✓ Describe agile methodologies and eXtreme programming. ✓ Explain Object Oriented Analysis and Design and the Rational Unified Process (RUP). BAC - Systems Development - Year 1- 2014 40 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall BAC - Systems Development - Year 1- 2014 41