How to combine create form and edit form?

Question

Yii

There is an Artist model. She has a relation Song;
Each artist has only one song.
The controller has two actions.

public function actionCreate()
{
    $model = new Artist();
    $this->render('update', array(
        'model' => $model,
    ));
}
public function actionUpdate()
{
    $id = Yii::app()->request->getQuery('id');
    $model = Artist::model()->with('Song')->findByPk($id);
    $this->render('update', array(
        'model' => $model,
    ));
}

In view form for editing. I will show one field that gives an error

<?php $form->dropDownListGroup($model->song, 'name'); ?>

So, an error appears in this field when creating an artist, since with a newly created model, you cannot access $model->song. How to make it beautiful, so that for a new model this field would be empty?

Answer 1

<?php $form->dropDownList($model->song, 'name', CHtml::listData(Song::model()->findAll(), 'id', 'name')); ?>