The RAD model is a linear sequential software development process that emphasizes an extremely short development cycle. The RAD model is a “high speed” adaptation of the linear sequential model in which rapid development is achieved by using a component-based construction approach. Used primarily for information systems applications, the RAD approach encompasses the following phases:
1. Business modeling
The information flow among business functions is modeled in a way that answers the following questions:
What information drives the business process?
What information is generated?
Who generates it?
Where does the information go?
Who processes it?
2. Data modeling
The information flow defined as part of the business modeling phase is refined into a set of data objects that are needed to support the business. The characteristic (called attributes) of each object is identified and the relationships between these objects are defined.
3. Process modeling
The data objects defined in the data-modeling phase are transformed to achieve the information flow necessary to implement a business function. Processing the descriptions are created for adding, modifying, deleting, or retrieving a data object.
4. Application generation
The RAD model assumes the use of the RAD tools like VB, VC++, Delphi etc… rather than creating software using conventional third generation programming languages. The RAD model works to reuse existing program components (when possible) or create reusable components (when necessary). In all cases, automated tools are used to facilitate construction of the software.
5. Testing and turnover
Since the RAD process emphasizes reuse, many of the program components have already been tested. This minimizes the testing and development time.