The Force.com platform uses the Model View Controller (MVC) architectural pattern to develop an application. Visualforce is an implementation of the MVC architecture. The MVC architecture can be illustrated as follows:
The MVC structure is explained as follows:
Model: The model specifies the structure of the data. The data model of the Force.com platform is defined by objects. The platform is designed to map every entity to an object.
View: The data is represented through the view. The page layouts and Visualforce pages are considered as the view of the MVC architecture.
Controller: In the Force.com platform, the business logic (rules and actions) that manipulates the data is considered the controller. Apex classes, triggers, workflows, validation rules, and approval processes are considered the controllers of the Force.com platform.