ALTER TABLE `vn`.`travelLog` 
CHANGE COLUMN `changedModel` `changedModel` ENUM('Travel', 'TravelThermograph') NOT NULL DEFAULT 'Travel',
MODIFY COLUMN changedModelId INT(11) NOT NULL,
MODIFY COLUMN oldInstance JSON NULL,
MODIFY COLUMN newInstance JSON NULL,
ADD INDEX IF NOT EXISTS `travelLog_changedModel` (`changedModel` ASC, `changedModelId` ASC, `originFk` ASC),
ADD INDEX IF NOT EXISTS `travelLog_originFk` (`originFk` ASC, `creationDate` ASC),
DROP INDEX IF EXISTS `originFk` ;