如何最好地設計DB在這種情況下

Question

一目瞭然，數據庫架構是這樣的：

架構必須處於第三範式（和我知道hotels.average_rating否則建議，試圖監督這一點，因爲數據庫還沒有完全設計）。這是一個旅遊推薦系統。

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. 的問題是：如何最好添加一個「用戶活動日誌」功能，存儲用戶已經參加的活動？請注意，這兩個地區和酒店都可以舉辦活動，而且我需要知道該活動是發生在某個地區還是酒店。參照完整性應得到保證。

2. 現在查詢（它應該使用JOIN不應該嗎？）其中列出了所有用戶和他們的活動與酒店ID 或區域ID一起。（如果需要，不適用的可以是NULL）。

簡單的解決方案更 - 所以最好不用存儲過程或任何其挖太多的MySQL特定的功能。

Answer 1

你的數據庫沒有正常化 - 你做這件事的方式看起來像一個海報孩子，爲什麼規範化是一個好主意。

hotels.average_rating？

WTF？

儘管可以對數據進行非規範化處理是有意義的，但這不是如何去做的。考慮用戶提交酒店評級時需要做什麼 - 您需要根據提交的所有評級重新計算價值。相反，如果您持有sum_of_ratings（甚至保留了當前的平均值）和許多評分，則可以根據酒店記錄和新評分計算新值，而無需查看其他評分。