    public function beforeSave () {
        $valid = parent::beforeSave ();
        if ($valid) {
            $table = Yii::app()->db->schema->tables[$this->myTableName];
            $existing = array_key_exists($this->fieldName, $table->columns) && 
                $table->columns[$this->fieldName] instanceof CDbColumnSchema;
            if($existing){ 
                $valid = $this->modifyColumn();
            }
        }
        return $valid;
    }
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.