Essentials of Systems Analysis and Design Joseph S

Essentials of Systems Analysis and Design Joseph S. Valacich Joey F. George Jeffrey A. Hoffer Appendix B Rapid Application Development and Case Tools B. 1 Copyright 2001 Prentice-Hall, Inc.

Learning Objectives ü Explain the Rapid Application Development (RAD) approach and how it differs from traditional approaches to information systems development ü Describe the systems development components essential to RAD ü Describe the typical components of a comprehensive CASE environment ü Describe how CASE tools can be used to support RAD B. 2

Learning Objectives ü Describe visual and emerging development tools and how they can be used to support RAD ü Discuss the conceptual pillars that support the RAD approach ü Explain the advantages and disadvantages of RAD as an exclusive systems development methodology B. 3

Rapid Applications Development (RAD) Systems development methodology created to decrease the time needed to design and implement information systems radically. Five key factors 1. 2. 3. 4. 5. B. 4 Extensive user involvement Joint Application Design sessions Prototyping Integrated CASE tools Code generators

The Process of Developing an Application Rapidly RAD is a general strategy rather than a single methodology Goals n n n B. 5 To analyze a business process rapidly To design a viable system solution through intense cooperation between users and developers To get the finished application into the hands of the users quickly Traditional SDLC steps are followed, but phases are combined Iteration is limited to design and development phases

Components of RAD User involvement is key to success Prototyping is conducted in sessions similar to Joint Application Design (JAD) Prototyping screens become screens within the production system CASE tools are used to design the prototypes B. 6

CASE and Visual Development Environments Computer-aided Software Engineering (CASE) n n Software tools that provide automated support for some portion of the systems development process Upper CASE w n Lower CASE w B. 7 CASE tools designed to support systems planning and selection, systems analysis, and systems design phases of the systems development life cycle CASE tools designed to support the systems implementation and operation phase of the systems development life cycle

CASE and Visual Development Environments Cross life cycle CASE n CASE tools designed to support activities that occur across multiple phases of the systems development life cycle Most CASE tools utilize a repository to store all diagrams, forms, models and report definitions B. 8

CASE and Visual Development Environments Types of CASE tools n n n Diagramming tools Computer display and report generators Analysis tools used to check for incomplete, inconsistent or incorrect specifications A central repository Documentation generators Code generators Form and report generators n B. 9 CASE tools that support the creation of system forms and reports in order to prototype how systems will look and feel to users

CASE and Visual Development Environments Code Generators n B. 10 CASE tools that enable the automatic generation of program and database definition code directly from the design documents, diagrams, forms and reports stored in the repository

Approaches to RAD James Martin’s pillars of RAD n n Tools People Methodology Management Software Tools n Case tools can be used for w Prototyping w Code generation B. 11

Approaches to RAD Martin’s RAD Life Cycle n n Systems requirement determination is done in context of a discussion of business problems and business areas User Design w End users and IS professionals participate in JAD workshops w CASE tools are used to support prototyping n Construction w Designer creates code using code generator w End user validates screens and other aspects of design n B. 12 Cutover w New system is delivered to end users

A Specific RAD Life Cycle Cambridge Technology Partners Implement five steps 1. 2. 3. 4. 5. B. 13 Scope Rapid solutions workshop Design Development Rollout

RAD Success Stories Hughes Space and Communications Company U. S. Navy Fleet Modernization First National Bank of Chicago B. 14

Advantages Disadvantages Dramatic time savings the systems More speed and lower cost may development effort lead to lower overall system quality Can save time, money and human effort Tighter fit between user requirements and system specifications Works especially well where speed of development is important Danger of misalignment of system developed via RAD with the business due to missing information May have inconsistent internal designs within and across systems Ability to rapidly change system design as demanded by users System optimized for users involved in RAD process Concentrates on essential system elements from user viewpoint B. 15 Possible violation of programming standards related to inconsistent naming conventions and inconsistent documentation Difficulty with module reuse for future systems Lack of scalability designed into system Lack of attention to later systems administration built into system Strong user stake and ownership of system High cost of commitment on the part of key user personnel

Summary Rapid Application Development Approach (RAD) Components of RAD CASE Tools Visual Environments Conceptual pillars that support RAD Advantages and Disadvantages of RAD B. 16