RAD (Rapid Application Development) Model

 

Rapid Application Development (RAD) is an incremental software development process model that emphasizes an exactly short development cycle. The RAD model is a "high speed" adaptation of the linear sequential model in which rapid development is achieved by using component based construction. If requirements are well understood and project scope is constrained the RAD process enables a development team to create a "fully functional system" within very short time period.

Business Modeling: The information flow among business function is modeled in a way that answer the following questions. What information drives the business process? What information is generated? Who generates it? Where does the information go? Who process it?

Data Modeling: Information flow defined as part of the business modeling phase is refined into a set of data objects to support the business. The characteristics (called attributes) of each objects are identified and the relationship between these objects defined.

Process Modeling: The data objects defined in the data modeling phase are transformed to achieve the information flow necessary to implement a business function. Process descriptions are created to adding, modifying, deleting or retrieving a data object.

Application Generation: RAD assumes the use of fourth generation techniques. Rather than creating software using conventional third generation programming languages the RAD process works to reuse existing program components (when necessary) in all cases, automated tools are used to facilitate construction of the software.

Testing and Turnover: Since the RAD process emphasize the reuse many of the program components have already been tested. This reduce overall testing time. However new components must be tested and all interfaces must be fully exercised.

The time constrained imposed on a RAD project demand "scalable scope". If a business application can be modularized in a way that enables each major function to be completed in less that three months, it is a candidate for RAD. Each major function can be addresses by a separate RAD team and then integrated to form a whole.