Lecture 19 Rapid Application Development 19.1 COSC4406: Software Engineering

Learning Objectives Explain the Rapid Application Development (RAD) approach and how it differs from traditional approaches to information systems development Explain the Rapid Application Development (RAD) approach and how it differs from traditional approaches to information systems development Describe the systems development components essential to RAD Describe the systems development components essential to RAD Discuss the conceptual pillars that support the RAD approach Discuss the conceptual pillars that support the RAD approach Explain the advantages and disadvantages of RAD as an exclusive systems development methodology Explain the advantages and disadvantages of RAD as an exclusive systems development methodology 19.2

Rapid Applications Development (RAD) Systems development methodology created to radically decrease the time needed to design and implement information systems radically. Five key factors 1.Extensive user involvement 2.Joint Application Design sessions 3.Prototyping 4.Integrated CASE tools 5.Code generators 19.3

The Process of Developing an Application Rapidly RAD is a general strategy rather than a single methodology Goals –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 19.4

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 19.5

Approaches to RAD Martin’s pillars of RAD –Four pillars ToolsPeopleMethodologyManagement –Conversion to RAD within organization should be done with a small group of well-trained and dedicated professionals, called a RAD cell –Over time, cell can grow until RAD is the predominant approach of the information systems unit 19.6

Approaches to RAD McConnell’s pillars of RAD –Four pillars Avoid classic mistakes Apply development fundamentals Manage risks to avoid catastrophic setbacks Apply schedule-oriented practices –Table 19-1 lists some of McConnell’s 36 classic development mistakes 19.7

Approaches to RAD McConnell’s pillars of RAD (continued) –Development mistakes Weak personnel –Employees that are not as well trained in skills necessary for success of the project Silver-bullet syndrome –Occurs when developers believe that a new and untried technology is all that is needed to cure the ills of any development project Feature creep –More and more features are added to a system over course of development Requirements gold-plating –Project may have more requirements than needed 19.8

Approaches to RAD Software tools –Case tools can be used for Prototyping Code generation Example: COOL:Gen –Visual Development Environments Visual Basic Delphi 19.9

Approaches to RAD Martin’s RAD Life Cycle –Systems requirement determination is done in context of a discussion of business problems and business areas –User Design End users and IS professionals participate in JAD workshops CASE tools are used to support prototyping –Construction Designer creates code using code generator End user validates screens and other aspects of design –Cutover New system is delivered to end users 19.10

RAD Success Stories Inprise/Borland’s Delphi –U.S. Navy Fleet Modernization Requirements –Move from three character-based systems to a unified, GUI-based system based on a single database Reasons for choosing Delphi –Support for rapid prototyping –Promise of re-use of components Outcome –System developed in 6 months –Estimated development savings of 50 percent –New system resulted in immediate 20 percent savings due to reduced maintenance costs 19.11

RAD Success Stories Inprise/Borland’s Delphi (continued) –First National Bank of Chicago Electronic Federal Tax Payment System Delphi enabled rapid prototyping and development 10 months of development time 125 programmers 250 million rows of data and 55 gigabytes of data on-line 19.12

RAD Success Stories VisualAge for Java –Comdata Modular Over the Road System (MOTRS) IBM Global Services chosen as vendor Servlets –Programming modules that expand the functions of the Web server Applets –Embedded code run from client browser Nine months to completion –Three months of research –Three months of coding –Three months of testing 19.13

AdvantagesDisadvantages Dramatic time savings the systems development effort More speed and lower cost may lead to lower overall system quality Can save time, money and human effort Danger of misalignment of system developed via RAD with the business due to missing information Tighter fit between user requirements and system specifications May have inconsistent internal designs within and across systems Works especially well where speed of development is important Possible violation of programming standards related to inconsistent naming conventions and inconsistent documentation Ability to rapidly change system design as demanded by users Difficulty with module reuse for future systems System optimized for users involved in RAD process Lack of scalability designed into system Concentrates on essential system elements from user viewpoint 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 19.14

Summary Rapid Application Development Approach (RAD) Components of RAD Conceptual pillars that support RAD RAD success stories Advantages and Disadvantages of RAD 19.15