Yii is high-performance component-based PHP framework for developing large- scale Web applications. It enable maximum reusability in Web programming and can significantly accelerate the development process. The Yii framework is free software. It is PHP framework based on Object oriented php5.Developed by Qiang Xue.who started to work on YII on 1st January 2008.Qiang Xue was with experience in development of frameworks PRADO is also famous framework for PHP was also developed by Qiang Xue. It is said that YII framework is best because it is based on DRY(Dont repeat yourself)design pattern.

Like most PHP frameworks, Yii is an MVC framework. Yii is design for serious Web application development. To use Yii framework in Web application need Web server supporting PHP 5.1.0 or higher. Yii is a pure OOP framework.

 The Yii framework is used to fix some drawbacks of the PRADO framework. For example, PRADO was slow when handling complex page and many controls were difficult to customize, while Yii is much easier and more efficient.

Yii implement model-view-controller (MVC) design pattern which is widely used in Web programming. In MVC model contain information and view contain elements of the user interface such as text, form inputs and the controller manages the communication between the model and the view.

Yii introduced front-controller called application which represents the execution context of request processing

Model-View-Controller It is architecture,currently considered an architectural pattern used in software engineering. Model View Controller (MVC) pattern creates application that separate different input logic, business logic, and UI logic of the application while providing a loose coupling between these elements.

Model :- A model represents single data object. It could be row in database table or form of user inputs.

View :- view is a PHP script contain elements of user interface.controller contain large chunk of logic view has name which is used to identify the view script file.

Controller :- controller creates applications that separate input logic ,business logic and UI design of application while providing loose coupling between these elements.

Installation of yii framework:

 Installation of Yii mainly involve the following two steps:

 Download Yii Framework from yiiframework.com.

 Then installing Yii, we may want to verify that our server satisfies all the requirements of using Yii.

YII built with help of Qiang Xue and use several other web technologies to enhance the power of YII Qiang Xue used .

PRADO :- prado is major source in development of YII.

Jquery :- Jquery is used in yii, Symphony and joomla were also used in development of yii.

Out of several frameworks few framework are famous :- CakePhp, Zend Framework,Symphony,Codeigniter, Prado .

Yii framework used in different projects :- web-based CRM application , the key feature of the project was building a custom framework above Yii, a web-portal for lawyers.

Google will display sitelink for each language instead of probably mixed up stuff.

we can split our website into real multi language portal. It is very fast and efficient.

If we use different subdomains for one site, the page rank of our main domain (e.g example.com) will probably suffer. Google itself state its better to use top-level domains instead of subdomains.For small multilanguage site use english url rules with one main domain.

Yii does not need to be installed under Web-accessible directory. Yii application has only one entry script which is usually the only file that needs to be exposed to Web users. Other PHP script including those from Yii should be protected from Web access since they may be exploited for hacking.