如何在MySQL中设计商城的优惠券表结构？

CREATE TABLE `coupons` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `name ` VARCHAR(100) NOT NULL,
  `type` ENUM('full_reduction', 'discount', 'free_shipping') NOT NULL,
  `value` DECIMAL(10,2) NOT NULL,
  `min_amount` DECIMAL(10,2) DEFAULT 0,
  `start_time` DATETIME NOT NULL,
  `end_time` DATETIME NOT NULL,
  `total_count` INT(11) NOT NULL,
  `claimed_count` INT(11) NOT NULL DEFAULT 0,
  PRIMARY KEY (`id`)
);

CREATE TABLE `user_coupons` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `user_id` INT(11) NOT NULL,
  `coupon_id` INT(11) NOT NULL,
  `claimed_time` DATETIME NOT NULL,
  `used_time` DATETIME DEFAULT NULL,
  PRIMARY KEY (`id`),
  INDEX (`user_id`),
  INDEX (`coupon_id`),
  FOREIGN KEY (`user_id`) REFERENCES `users` (`id`),
  FOREIGN KEY (`coupon_id`) REFERENCES `coupons` (`id`)
);

CREATE TABLE `coupon_scenes` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `coupon_id` INT(11) NOT NULL,
  `product_id` INT(11) DEFAULT NULL,
  `cateGory_id` INT(11) DEFAULT NULL,
  `order_id` INT(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  FOREIGN KEY (`coupon_id`) REFERENCES `coupons` (`id`),
  FOREIGN KEY (`product_id`) REFERENCES `products` (`id`),
  FOREIGN KEY (`category_id`) REFERENCES `categories` (`id`),
  FOREIGN KEY (`order_id`) REFERENCES `orders` (`id`)
);