ALTER TABLE `bus_shift_year` 
ADD COLUMN `bus_buddy_bdr` INT NULL COMMENT 'Driver companion.' AFTER `bus_serial_bdr`,
ADD INDEX `fk_relationship_82_idx` (`bus_buddy_bdr` ASC);


ALTER TABLE `bus_shift_year` 
ADD CONSTRAINT `fk_bus_shift_year_bus_driver`
  FOREIGN KEY (`bus_buddy_bdr`)
  REFERENCES `bus_driver` (`serial_bdr`)
  ON DELETE NO ACTION
  ON UPDATE NO ACTION;