SDLC Models

SDLC models are a package of steps and procedure, which may differ model wise. Following are the most important and popular SDLC models followed in the industry:

•  Waterfall Model

• Iterative Model

• Spiral Model

• V-Model

• Big Bang Model

Other related methodologies are Agile Model, RAD Model, Rapid Application Development and Prototyping Models.

Waterfall Model

Waterfall model is a basic approach of SDLC implementation. It is also know as linear sequential life cycle model. It is very easy to use and understand. In waterfall model each phase must be complete before next to be start. Top to down approach is followed. The flow of data and control is accomplished process by process.



Design:

Advantage:

• It is easy to manage due to the rigidity of the model – each phase has specific deliverables and a review process.
• Waterfall model works well for smaller projects where requirements are very well understood.
• This model is simple and easy to understand and use.
• In this model phases are processed and completed one at a time. Phases do not overlap.

Disadvantage:

• Once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.
• No working software is produced until late during the life cycle.
• High amounts of risk and uncertainty.
• Not a good model for complex and object-oriented projects.
• Poor model for long and ongoing projects.
• Not suitable for the projects where requirements are at a moderate to high risk of changing