Question

Web应用程序PHP，Mysql。用户可以撰写文章。如何构建允许用户订阅（跟随）其他用户文章然后查看订阅用户添加的最后文章列表的算法？算法必须扩展，以便一个用户可以订阅10 000个用户，10 000个用户可以订阅一个用户，所有部分都可以快速工作 - 添加新文章和用户查找订阅用户的最后文章时。

Answer 1

create table `user`(
  `id` INT(10) PRIMARY KEY NOT NULL AUTO_INCREMENT
);

create table `subscribes_to` (
  `subscriber_user_id` INT(10) NOT NULL,
  `subscribed_to_user_id` INT(10) NOT NULL, # Receiver of the subscription  
  PRIMARY KEY(`subscribe_user_id`, `subribed_to_user_id`),
  KEY `subscriber(`subscribe_user_id`),
  KEY `subscribed(`subscribed_to_user_id`);
);


# Users subscribed to role 100
SELECT distinct u.* FROM user u
  JOIN subscribes_to st ON st.subscriber_user_id = u.id
WHERE
  st.subscribded_to_user_id = 100;

# User 100's subsriptions   
SELECT distinct u.* FROM user u
  JOIN subscribes_to st ON st.subscribded_to_user_id = u.id
WHERE
  st.subscriber_user_id = 100;

显示与文章关系的附加架构：

文章（ id int（10）UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT， title VARCHAR（255）， body文字， date_created DATETIME， date_updated DATETIME， author_user_id int（10））;

# Create new article
INSERT INTO `article` VALUES (NULL, "Hello", "This is the body", NOW(), NOW(), 1);

# Find the last 10 articles posted that user 15 suscribes to
# the author of
SELECT a.* FROM article a
    JOIN user ON u.id = a.author_user_id
    JOIN subscribes_to st ON st.subscribed_to_user_id = u.id
WHERE st.subscriber_user_id = 15 ORDER BY a.date_created DESC LIMIT 10;

可扩展的订阅算法

1 个答案: