RAD is incremental software development process model that allows usable
systems to be built in extremely short development cycle using a
component based construction approach. If the requirements are well
understood and defined, and the project scope is constraint, the RAD
process enables a development team to create a fully functional system
with in very short time period.
The RAD model contains the following phases:
1. Business Modeling:
The information flow among business functions is modeled in a way that answers questions like what information drives the business process, what information is generated, who generates it, where does the information go, who process it and so on.
2. Data Modeling:
The information defined as part of the business modeling phase is refined into a set of data objects (entities) that are needed to support the business. The characters of each entity (called attributes) are identified and the relation between these data objects (entities) are defined.
3. Process Modeling:
The data object defined in the data modeling phase are transformed to achieve the information flow necessary to implement a business function. Processing descriptions are created for adding, modifying, deleting or retrieving a data object.
4. Application Generation:
RAD assumes the use of RAD tools like VB, VC++, Delphi etc rather than creating software using conventional third 3G programming languages. RAD works to reuse the existing program, components or create reusable components.
5. Testing and Turn over:
As RAD process emphasizes reuse, many of the programs components have already been tested. This reduces overall testing time. But new components must be tested and all interfaces must be completely exercised.
Advantages
• Increased Speed - RAD reduces the development time as reusability of components help to speed up development. Modularized functions that makes easy to work with.
Disadvantages
• Reduced Scalability - As RAD focuses on development of a prototype that is iteratively developed into a full system, the delivered resolution may lack the scalability of a resolution that was designed as a full application from the start.
• Reduced Features - As RAD focuses on delivery of application in short time some of the features may be moved to later versions which results in incomplete application development.
The RAD model contains the following phases:
1. Business Modeling:
The information flow among business functions is modeled in a way that answers questions like what information drives the business process, what information is generated, who generates it, where does the information go, who process it and so on.
2. Data Modeling:
The information defined as part of the business modeling phase is refined into a set of data objects (entities) that are needed to support the business. The characters of each entity (called attributes) are identified and the relation between these data objects (entities) are defined.
3. Process Modeling:
The data object defined in the data modeling phase are transformed to achieve the information flow necessary to implement a business function. Processing descriptions are created for adding, modifying, deleting or retrieving a data object.
4. Application Generation:
RAD assumes the use of RAD tools like VB, VC++, Delphi etc rather than creating software using conventional third 3G programming languages. RAD works to reuse the existing program, components or create reusable components.
5. Testing and Turn over:
As RAD process emphasizes reuse, many of the programs components have already been tested. This reduces overall testing time. But new components must be tested and all interfaces must be completely exercised.
Advantages
• Increased Speed - RAD reduces the development time as reusability of components help to speed up development. Modularized functions that makes easy to work with.
Disadvantages
• Reduced Scalability - As RAD focuses on development of a prototype that is iteratively developed into a full system, the delivered resolution may lack the scalability of a resolution that was designed as a full application from the start.
• Reduced Features - As RAD focuses on delivery of application in short time some of the features may be moved to later versions which results in incomplete application development.