1-01:Prototyping an Application

Chapter 1-1: Overview of Application Design

Prototyping an Application

One method of system design involves the development of a preliminary specification-driven application to use as a prototype during the definition stage of an application project. Prototyping is an iterative design method by which you develop sample screens and reports, review them with the intended end users, modify the samples, and repeat the review process until the samples are satisfactory. APPX is an excellent prototyping tool because you can specify and modify screen images and reports very quickly. After you and the end users reach a mutual understanding about the basic structural and operational requirements of an application, you can supplement the basic specifications with ILF routines to address the more complex processing requirements.

There are several advantages of using a prototyping approach:

· With APPX, you can continue to enhance the prototype application you develop until it is complete enough to use as the real application in production. You do not have to discard the prototype and start over after all the requirements are defined.

· Prototyping allows you to minimize the coding and testing cycle because you actually begin testing as soon as you review the prototype application with the end users.

· There is less need to freeze the design requirements before you can begin productive work and demonstrate some of the capabilities of the proposed application. Users always find it easier to critique examples rather than concepts (i.e., written specifications).

· APPX’s facilities provide ease of modification and enhancement; you do not have to discourage users from proposing changes and additional features.

· Prototyping encourages earlier and more productive involvement of end users, reducing the chances of finding design flaws in the latter stages of development.

APPX Application Design Manual (01/13/03)