How to upload image(photo), and path entry in database with update functionality

..
//form options array...
'htmlOptions' => array(
'enctype' => 'multipart/form-data',
),
...
..
//Other elements
..
..
<divclass="row">
<?phpecho$form->labelEx($model,'image'); ?>
<?phpechoCHtml::activeFileField($model, 'image'); ?>// by this we can upload image
<?phpecho$form->error($model,'image'); ?>
</div>
<?phpif($model->isNewRecord!='1'){?>
<div class="row">
<?phpechoCHtml::image(Yii::app()->request->baseUrl.'/banner/'.$model->image,"image",array("width"=>200)); ?>  // Image shown here if page is update page
</div>
..
..
Other elements
..
..

array('image', 'file','types'=>'jpg, gif, png', 'allowEmpty'=>true, 'on'=>'update'), // this will allow empty field when page is update (remember here i create scenario update)

array('title, image', 'length', 'max'=>255, 'on'=>'insert,update'),

publicfunctionactionCreate()
{
$model=newBanner;  // this is my model related to table
if(isset($_POST['Banner']))
{
$rnd = rand(0,9999);  // generate random number between 0-9999
$model->attributes=$_POST['Banner'];

$uploadedFile=CUploadedFile::getInstance($model,'image');
$fileName = "{$rnd}-{$uploadedFile}";  // random number + file name
$model->image = $fileName;

if($model->save())
{
$uploadedFile->saveAs(Yii::app()->basePath.'/../banner/'.$fileName);  // image will uplode to rootDirectory/banner/
$this->redirect(array('admin'));
}
}
$this->render('create',array(
'model'=>$model,
));
}

publicfunctionactionUpdate($id)
{
$model=$this->loadModel($id);

if(isset($_POST['Banner']))
{
$_POST['Banner']['image'] = $model->image;
$model->attributes=$_POST['Banner'];

$uploadedFile=CUploadedFile::getInstance($model,'image');

if($model->save())
{
if(!empty($uploadedFile))// check if uploaded file is set or not
{
$uploadedFile->saveAs(Yii::app()->basePath.'/../banner/'.$model->image);
}
$this->redirect(array('admin'));
}

}

$this->render('update',array(
'model'=>$model,
));
}