Overview========Yii applications are organized according to the [model-view-controller (MVC)](http://wikipedia.org/wiki/Model-view-controller)design pattern. [Models](structure-models.md) represent data, business logic and rules; [views](structure-views.md)are output representation of models; and [controllers](structure-controllers.md) take input and convertit to commands for [models](structure-models.md) and [views](structure-views.md).Besides MVC, Yii applications also have the following entities:*[entry scripts](structure-entry-scripts.md): they are PHP scripts that are directly accessible by end users. They are responsible for starting a request handling cycle.*[applications](structure-applications.md): they are globally accessible objects that manage application components and coordinate them to fulfill requests.*[application components](structure-application-components.md): they are objects registered with applications and provide various services for fulfilling requests.*[modules](structure-modules.md): they are self-contained packages that contain complete MVC by themselves. An application can be organized in terms of multiple modules.*[filters](structure-filters.md): they represent code that need to be invoked before and after the actual handling of each request by controllers.*[widgets](structure-widgets.md): they are objects that can be embedded in [views](structure-views.md). They may contain controller logic and can be reused in different views.The following diagram shows the static structure of an application:![Static Structure of Application](images/application-structure.png)