LetterMacro::beforeSave PHP Метод

    public function beforeSave()
    {
        switch ($this->type) {
            case 'site':
                $this->firm_id = null;
                $this->subspecialty = null;
                break;
            case 'subspecialty':
                $this->firm_id = null;
                $this->site_id = null;
                break;
            case 'firm':
                $this->subspecialty_id = null;
                $this->site_id = null;
                break;
        }
        return parent::beforeSave();
    }