public function actionUpdate($id) {
    $model = $this->findModel($id);

    if ($model->load($_POST) && $model->save()) {
        return $this->redirect(['view', 'id' => $model->id]);
    } else {
        return $this->render('update', [
            'model' => $model,
        ]);
    }
}

public function beforeSave($insert) {
    if ($this->isAttributeChanged('name')) {
        rename($this->getOldAttribute('name') . '.pdf', $this->name . '.pdf');
    }

    parent::beforeSave($insert);
}

public function beforeSave() {

        if ($this->isNewRecord) {
            $this->insertDate = new CDbExpression('NOW()');
        } else {
            $this->updateDate = new CDbExpression('NOW()');
        }

        return parent::beforeSave();
    }

public function beforeSave() {
        $this->date = date('Y-m-d', $this->date);
        return parent::beforeSave();
    }