Gii is the web-based code generation tool of Yii Framework. While you can add your own code templates to Gii, it is equipped with templates for Controllers, CRUDs, Forms, Models and Modules.
Starting from version 1.1.2, Yii is equipped with a Web-based code generation tool called Gii. It supersedes the previous yiic shell generation tool, which runs on command line.
Detailed instructions about Gii can be found here: http://www.yiiframework.com/doc/guide/1.1/en/topics.gii