In yii we can create our basic code for 'CREATE',,'UPDATE','READ','DELETE' operations. for enable this functionality we need to enable curd. For enable curd go to your main.php file and find keyword 'gii' and you will see like this

   /* 'modules'=>array(
      'gii'=>array(
       'class'=>'system.gii.GiiModule',
       'password'=>'gii',
       'ipFilters'=>array('*','::1'),
       'generatorPaths' => array(
            'bootstrap.gii'
       ),
      ),
     ),*/

uncommnet this section and you can access CURD operation

    'modules'=>array(
      'gii'=>array(
       'class'=>'system.gii.GiiModule',
       'password'=>'gii',
       'ipFilters'=>array('*','::1'),
       'generatorPaths' => array(
            'bootstrap.gii'
       ),
      ),
     ),