Yii framework (фреймворк) - a relatively young (the first version was released in 2008, although the history is longer), but promising, rapidly developing and functional web development tool, in other words, php framework. It uses the MVC paradigm.
MVC principle in web programming (Model - View - Controller) is one of the most successful ideas to date. The MVC principle is intuitive at first glance, but not very simple when delving into it. First, let's consider what it is intended for.