A controller can send commands to its associated view to change the view’s presentation of the model (e.g., by scrolling through a document). It can also send commands to the model to update the model’s state (e.g., editing a document). A model notifies its associated views and controllers when there has been a change in its state. This notification allows the views to produce updated output, and the controllers to change the available set of commands. A view requests from the model the information that it needs to generate an output representation. Some Examples: 1. Visual Force pages, Page Layouts, Tabs comes under View Layer of Model View controller . 2. Workflows, Apex Classes, Triggers, Validation Rules comes under Controller part in Model View controller . 3. Objects, Fields, Relationships comes under Model Layer of Model View Controller .
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