如何在Yii中生成一行的平均值，然后使用afterSave(）保存 - How to make an average in a row and then save it using afterSave() in Yii

How to make an average in a row and then save it using afterSave() in Yii

在一个表中，我有Notas表的3列nota1、nota2、nota3
我想计算nota1，nota2，nota3的平均值
然后我想使用beforeSave（）方法保存nota_final字段的平均结果

这是我在Notas.php模型中的代码：

    public function getAvg()
     {
        $avg = Yii::app()->db->createCommand()
        ->select('(nota1 + nota2 + nota3)/3 as NotaFinal')
        ->from('notas')   
        ->queryRow();
        return $avg;
    }
    protected function afterSave()
    {
        if($this->isNewRecord){
        $this->nota_final->Avg();
        $this->isNewRecord= false;
        $this->nota_final->saveAttributes($_POST['nota_final']);
        if($model->save() == false) var_dump($model->errors);
        }
    return parent::afterSave(); 
    }

它没有保存平均值，也没有显示任何错误。

怎么了？

my View/notas_form.php

 tr>
                    <td><div class="row2">
                    <?php echo $form->labelEx($model,'nota1'); ?>
                    <?php echo $form->textField($model, 'nota1', array('maxlength'=>'3')); ?>
                    <?php echo $form->error($model,'nota1'); ?>
                </div></td>
                    <td>
                        <div class="row2">
                    <?php echo $form->labelEx($model,'nota2'); ?>
                    <?php echo $form->textField($model,'nota2', array('maxlength'=>'3', 'input'=>'20px')); ?>
                    <?php echo $form->error($model,'nota2'); ?>
                </div>
                </td>
                <td>
                <div class="row2">
                    <?php echo $form->labelEx($model,'nota3'); ?>
                    <?php echo $form->textField($model,'nota3', array('maxlength'=>'3')); ?>
                    <?php echo $form->error($model,'nota3'); ?>
                </div>
                <td>
                <div class="row2">
                    <?php echo $form->labelEx($model,'nota_final'); ?>
                    <?php echo $form->textField($model, 'nota_final', array('readOnly'=>true)); ?>
                    <?php echo $form->error($model,'nota_final'); ?>
                </div>

public function getAvg() // remove this method
{
}
protected function beforeSave() // change to beforeSave()
{
    if($this->isNewRecord) {
        // Copy attributes from $_POST
        $this->nota_final->saveAttributes($_POST['nota_final']);
        // Calculate average
        $this->nota_final->avg = 
           ($this->nota_final->nota1 + $this->nota_final->nota2 + 
            $this->nota_final->nota3) / 3;
        // DO NOT NEED TO CALL ->save() here, it will result in loop. 
        // Do it in your controller, and this beforeSave method will be triggered
    }
    return parent::beforeSave(); // change to beforeSave
}