public function getFieldId()
    {
        if (isset($this->_data['gtap_id_app_field']) && $this->_data['gtap_id_app_field']) {
            return FieldsDefinition::makeKey(
                    FieldMaintenanceModel::APPOINTMENTS_NAME,
                    $this->_data['gtap_id_app_field']
                    );
        }
    }