-- dice_reward 表增加自增主键 id，原复合主键改为唯一索引以保证 (tier,direction,end_index) 不重复
ALTER TABLE `dice_reward` DROP PRIMARY KEY;
ALTER TABLE `dice_reward` ADD COLUMN `id` bigint unsigned NOT NULL AUTO_INCREMENT FIRST, ADD PRIMARY KEY (`id`);
ALTER TABLE `dice_reward` ADD UNIQUE KEY `uk_tier_direction_end` (`tier`, `direction`, `end_index`);