How to debug sql in yii

// remove the following lines when in production mode 
defined('YII_DEBUG') or define('YII_DEBUG',true); 
// specify how many levels of call stack should be shown in each log message 
defined('YII_TRACE_LEVEL') or define('YII_TRACE_LEVEL',3); 
//app use time 
//defined('YII_BEGIN_TIME') or define('YII_BEGIN_TIME',microtime(true));

'errorHandler'=>array( 
  // use 'site/error' action to display errors 
  'errorAction'=>'site/error', 
), 
'log'=>array( 
  'class'=>'CLogRouter', 
  'routes'=>array( 
    array( 
      'class'=>'CFileLogRoute', 
      'levels'=>'error, warning', 
    ), 
    // 下面显示页面日志 
    array( 
      'class'=>'CWebLogRoute', 
      'levels'=>'trace',   //级别为trace 
      'categories'=>'system.db.*' //只显示关于数据库信息,包括数据库连接,数据库执行语句 
    ),    
  ), 
),

'log'=>array( 
   'class'=>'CLogRouter', 
   'routes'=>array( 
     array( 
       'class'=>'ext.yii-debug-toolbar.YiiDebugToolbarRoute', 
       'ipFilters'=>array('127.0.0.1','192.168.1.215'), 
     ), 
   ), 
 ),

'enableProfiling'=>true, 
'enableParamLogging'=>true,