如何最好地设计DB在这种情况下

Question

一目了然，数据库架构是这样的：

架构必须处于第三范式（和我知道hotels.average_rating否则建议，试图监督这一点，因为数据库还没有完全设计）。这是一个旅游推荐系统。

的SQL：

SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO"; 
SET time_zone = "+00:00"; 

CREATE TABLE `activities` (
    `activity_id` int(10) unsigned NOT NULL AUTO_INCREMENT, 
    `activity_name` varchar(277) COLLATE utf8_bin NOT NULL, 
    PRIMARY KEY (`activity_id`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `bookings` (
    `from_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
    `to_date` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', 
    `belong_user` int(10) unsigned NOT NULL, 
    `belong_hotel` int(10) unsigned NOT NULL, 
    `rating` int(3) unsigned NOT NULL, 
    KEY `belong_user` (`belong_user`), 
    KEY `belong_hotel` (`belong_hotel`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `countries` (
    `cuntry_id` int(10) unsigned NOT NULL AUTO_INCREMENT, 
    `country_name` varchar(20) COLLATE utf8_bin NOT NULL, 
    PRIMARY KEY (`cuntry_id`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `hotels` (
    `hotel_id` int(10) unsigned NOT NULL AUTO_INCREMENT, 
    `hotel_name` varchar(128) COLLATE utf8_bin NOT NULL, 
    `hotel_stars` int(3) NOT NULL, 
    `hotel_description` text COLLATE utf8_bin NOT NULL, 
    `average_price` float unsigned NOT NULL, 
    `average_rating` float unsigned NOT NULL, 
    `total_rooms` int(10) unsigned NOT NULL, 
    `free_rooms` int(10) unsigned NOT NULL, 
    `belong_region` int(10) unsigned NOT NULL, 
    PRIMARY KEY (`hotel_id`), 
    KEY `belong_region` (`belong_region`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `hotels_activity_offers` (
    `belong_hotel` int(10) unsigned NOT NULL, 
    `belong_activity` int(10) unsigned NOT NULL, 
    UNIQUE KEY `belong_hotel_2` (`belong_hotel`,`belong_activity`), 
    KEY `belong_hotel` (`belong_hotel`), 
    KEY `belong_activity` (`belong_activity`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `regions` (
    `region_id` int(10) unsigned NOT NULL AUTO_INCREMENT, 
    `belong_country` int(10) unsigned NOT NULL, 
    `region_name` varchar(255) COLLATE utf8_bin NOT NULL, 
    PRIMARY KEY (`region_id`), 
    KEY `belong_country` (`belong_country`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `regions_activity_offers` (
    `belong_region` int(10) unsigned NOT NULL, 
    `belong_activity` int(10) unsigned NOT NULL, 
    KEY `belong_region` (`belong_region`), 
    KEY `belong_activity` (`belong_activity`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `users` (
    `user_id` int(10) unsigned NOT NULL AUTO_INCREMENT, 
    `username` varchar(20) COLLATE utf8_bin NOT NULL, 
    `password` varchar(40) COLLATE utf8_bin NOT NULL COMMENT 'MD5', 
    `first_name` varchar(20) COLLATE utf8_bin NOT NULL, 
    `last_name` varchar(20) COLLATE utf8_bin NOT NULL, 
    `email` varchar(255) COLLATE utf8_bin NOT NULL, 
    `is_admin` tinyint(1) NOT NULL, 
    `is_active` tinyint(1) NOT NULL, 
    PRIMARY KEY (`user_id`), 
    KEY `is_active` (`is_active`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 

CREATE TABLE `users_favourite_activities` (
    `belong_user` int(10) unsigned NOT NULL, 
    `belong_activity` int(10) unsigned NOT NULL, 
    UNIQUE KEY `belong_user_2` (`belong_user`,`belong_activity`), 
    KEY `belong_user` (`belong_user`), 
    KEY `belong_activity` (`belong_activity`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin; 


ALTER TABLE `bookings` 
    ADD CONSTRAINT `bookings_ibfk_3` FOREIGN KEY (`belong_hotel`) REFERENCES `hotels` (`hotel_id`) ON DELETE CASCADE, 
    ADD CONSTRAINT `bookings_ibfk_2` FOREIGN KEY (`belong_user`) REFERENCES `users` (`user_id`) ON DELETE CASCADE; 

ALTER TABLE `hotels` 
    ADD CONSTRAINT `hotels_ibfk_1` FOREIGN KEY (`belong_region`) REFERENCES `regions` (`region_id`) ON DELETE CASCADE; 

ALTER TABLE `hotels_activity_offers` 
    ADD CONSTRAINT `hotels_activity_offers_ibfk_2` FOREIGN KEY (`belong_activity`) REFERENCES `activities` (`activity_id`) ON DELETE CASCADE, 
    ADD CONSTRAINT `hotels_activity_offers_ibfk_1` FOREIGN KEY (`belong_hotel`) REFERENCES `hotels` (`hotel_id`) ON DELETE CASCADE; 

ALTER TABLE `regions` 
    ADD CONSTRAINT `regions_ibfk_1` FOREIGN KEY (`belong_country`) REFERENCES `countries` (`cuntry_id`) ON DELETE CASCADE; 

ALTER TABLE `regions_activity_offers` 
    ADD CONSTRAINT `regions_activity_offers_ibfk_2` FOREIGN KEY (`belong_activity`) REFERENCES `activities` (`activity_id`) ON DELETE CASCADE, 
    ADD CONSTRAINT `regions_activity_offers_ibfk_1` FOREIGN KEY (`belong_region`) REFERENCES `regions` (`region_id`) ON DELETE CASCADE; 

ALTER TABLE `users_favourite_activities` 
    ADD CONSTRAINT `users_favourite_activities_ibfk_1` FOREIGN KEY (`belong_user`) REFERENCES `users` (`user_id`) ON DELETE CASCADE, 
    ADD CONSTRAINT `users_favourite_activities_ibfk_2` FOREIGN KEY (`belong_activity`) REFERENCES `activities` (`activity_id`) ON DELETE CASCADE; 

1. 的问题是：如何最好添加一个“用户活动日志”功能，存储用户已经参加的活动？请注意，这两个地区和酒店都可以举办活动，而且我需要知道该活动是发生在某个地区还是酒店。参照完整性应得到保证。

2. 现在查询（它应该使用JOIN不应该吗？）其中列出了所有用户和他们的活动与酒店ID 或区域ID一起。（如果需要，不适用的可以是NULL）。

简单的解决方案更 - 所以最好不用存储过程或任何其挖太多的MySQL特定的功能。

Answer 1

你的数据库没有正常化 - 你做这件事的方式看起来像一个海报孩子，为什么规范化是一个好主意。

hotels.average_rating？

WTF？

尽管可以对数据进行非规范化处理是有意义的，但这不是如何去做的。考虑用户提交酒店评级时需要做什么 - 您需要根据提交的所有评级重新计算价值。相反，如果您持有sum_of_ratings（甚至保留了当前的平均值）和许多评分，则可以根据酒店记录和新评分计算新值，而无需查看其他评分。