Column name must be either a string or an array

Yii 1.1
1

Hi

class CommentRequest extends CActiveRecord {
/**
* @return string the associated database table name
*/
public function tableName() {
return ‘Comment_Request’;
}

/**
 * @return array validation rules for model attributes.
 */
public function rules() {
	// NOTE: you should only define rules for those attributes that
	// will receive user inputs.
	return array(
		array('id_rezerwacja', 'required'),
		array('id_rezerwacja', 'numerical',),
		array('opinion_code', 'safe',),
		// The following rule is used by search().
		// @todo Please remove those attributes that should not be searched.
		array('id, id_rezerwacja, opinion_code', 'safe', 'on' => 'search'),
	);
}



			Yii::trace(print_r($commentRequest, true));
			$commentRequest->opinion_code = '';
			$commentRequest->update(array('opinion_code'));
			$commentRequest->save();
			Yii::trace(print_r($commentRequest, true));

In lines update and save view error ‘Column name must be either a string or an array.’

Please help my.