Application Structure

Applications

Applications are objects that govern the overall structure and lifecycle of Yii application systems. Each Yii application system contains a single application object which is created in the entry script and is globally accessible through the expression \Yii::$app.

Entry Scripts

Entry scripts are the first step in the application bootstrapping process. An application (either Web application or console application) has a single entry script. End users make requests to entry scripts which instantiate application instances and forward the requests to them.

Entry scripts for Web applications must be stored under Web accessible directories so that they can be accessed by end users. They are often named as index.php, but can also use any other names, provided Web servers can locate them.

Overview

Yii applications are organized according to the model-view-controller (MVC) architectural pattern. Models represent data, business logic and rules; views are output representation of models; and controllers take input and convert it to commands for models and views.