Modern Systems Analysis and Design PDF

Modern Systems Analysis and Design Eighth Edition, Global Edition Joseph S. Valacich Joey F. George Chapter 1 The Systems Development Environment Chapter 1 Copyright © 2...

Modern Systems Analysis and Design Eighth Edition, Global Edition Joseph S. Valacich Joey F. George Chapter 1 The Systems Development Environment Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-1 Learning Objectives ✓ Define information systems analysis and design. ✓ Describe the information systems development life cycle (SDLC). ✓ Explain computer-aided software engineering (CASE) tools. ✓ Describe Agile Methodologies and eXtreme Programming. ✓ Explain object-oriented analysis and design and the Rational Unified Process (RUP). Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-2 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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-3 Introduction (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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-4 Introduction (Cont.) FIGURE 1-1 An organizational approach to systems analysis and design is driven by methodologies, techniques, and tools. Sources: Mitarart/Fotolia, PaulPaladin/Fotolia Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-5 A Modern Approach to Systems Analysis and Design ◼ 1950s: focus on efficient automation of existing processes ◼ 1960s: advent of procedural third generation languages (3GL) faster and more reliable computers ◼ 1970s: system development becomes more like an engineering discipline Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-6 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 and smart phones, component-based applications, per-use cloud-based application services. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-7 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. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-8 Systems Development Life Cycle (SDLC) ◼ Traditional methodology used to develop, maintain, and replace information systems ◼ Phases in SDLC:  Planning  Analysis  Design  Implementation  Maintenance Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-9 Standard and Evolutionary Views of SDLC FIGURE 1-3 Evolutionary model FIGURE 1-2 Systems development life cycle Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-10 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 ◼ Design – a description of the recommended solution is converted into logical and then physical system specifications Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-11 Systems Development Life Cycle (SDLC) (Cont.) ◼ Logical design – all functional features of the system chosen for development in analysis are described independently of any computer platform ◼ 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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-12 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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-13 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-14  A Specialized Systems Development Life Cycle Figure 1-7 Microsoft’s Security Development Lifecycle (SDL) Training Verification Release Response focuses on focuses on makes These are like traditional deals with security. product product SDLC’s analysis, design, and security quality available implementation. problems assurance. for general that come up use. after product (Source: http://www.microsoft.com/security/sdl/default.aspx. release. Used by permission.) Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-15 The Heart of the Systems Development Process FIGURE 1-8 FIGURE 1-9 Analysis–design–code–test loop The heart of systems development Current practice combines analysis, design, and implementation into a single iterative and parallel process of activities. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-16 Traditional Waterfall SDLC One phase begins when another completes, with little backtracking and looping. FIGURE 1-10 Traditional waterfall SDLC Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-17 Problems with Waterfall Approach ◼ Feedback ignored, milestones lock in design specs even when conditions change ◼ Limited user involvement (only in requirements phase) ◼ Too much focus on milestone deadlines of SDLC phases to the detriment of sound development practices Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-18 Different Approaches to Improving Development ◼ CASE Tools ◼ Agile Methodologies ◼ eXtreme Programming Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-19 Computer-Aided Software Engineering (CASE) Tools ◼ Diagramming tools enable graphical representation. ◼ Computer displays and report generators help prototype how systems “look and feel”. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-20 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. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-21 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. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-22 CASE Tools (Cont.) Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-23 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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-24 The Agile Methodologies group argues that software development methodologies adapted from engineering generally do not fit with real- world software development. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-25 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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-26 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-27 eXtreme Programming ◼ Short, incremental development cycles ◼ Automated tests ◼ Two-person programming teams ◼ Coding, testing, listening, designing Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-28 eXtreme Programming (Cont.) ◼ Coding and testing operate together ◼ Advantages:  Communication between developers  High level of productivity  High-quality code Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-29 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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-30 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 Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-31 Rational Unified Process (RUP) ◼ An object-oriented systems development methodology ◼ Establishes four phase of development: inception, elaboration, construction, and transition  Each phase is organized into a number of separate iterations. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-32  FIGURE 1-11 Phases of OOSAD-based development Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-33 Our Approach to Systems Development ◼ Criticisms of SDLC  Forcing timed phases on intangible processes (analysis and design) is doomed to fail  Too much formal process and documentation slows things down  Cycles are not necessarily waterfalls ◼ And yet the concept of a cycle is in all methodologies. So, SDLC is a valuable model that has many variations. Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-34 Summary ◼ In this chapter you learned how to: ✓ Define information systems analysis and design. ✓ Describe the information systems development life cycle (SDLC). ✓ Explain computer-aided software engineering (CASE) tools. ✓ Describe Agile Methodologies and eXtreme Programming. ✓ Explain object-oriented analysis and design and the Rational Unified Process (RUP). Chapter 1 Copyright © 2017 Pearson Education, Ltd. 1-35