Joomla! Documentation™

Components in Joomla Core (and indeed Generally in the Joomla ecosystem) follow the Model-View-Controller (MVC) design pattern. This pattern separates the data gathering (Model), presentation (View) and user interaction (Controller) activities of a component. Such separation allows for expanding or revising properties and methods of one section without requiring additional changes to the other sections. Please see the MVC tutorial, then select a Joomla! version for an explanation of the MVC structure.