0

我用 php(pdo) 和 mysql 做了一个简单的追随者系统。我的问题是，

假设有一个 ID 号为 99 的用户名 Mike。Mike 有两个关注者，Greg(id = 77) 和 Jenny(id = 88)

Greg 的关注列表是这样的 (1,2,3,4,99)，Jenny 的关注列表是这样的 (5,6,99,7)

我想做的是，当 Mike(99) 删除他的帐户时，我想从 Greg(77) 和 Jenny(88) 的以下列表中删除 ID 号 99。

名为“mytable”的表有 3 个字段。id（INT），following_list（文本），follower_list（文本）。

几天来我一直在努力解决这个问题。谁能给我一些建议？提前非常感谢你！！！

下面是我的更新功能

public function update_following_list(){
   // $this->myid is Mike's id number(99) who is about to delete his account
   // Selecting the list of people following Mike
   $query = "SELECT 'follower_list' FROM 'mytable' WHERE 'id' = $this->myid";
   $result = $this->dbc->query($query);
      foreach($result as $row){
      $this->follower_list = $row['follower_list'];
      // When I echo $this->follower_list, I get 77,88

      // Now querying Greg(77) and Jenny(88)'s following_lists, which have Mike's id number(99) in them.
      $query = "SELECT 'following_list' FROM 'mytable' WHERE 'id' IN ($this->follower_list)";
      $result = $this->dbc->query($query);
         foreach($result as $row){
         $this->following_list = $row['following_list'];
         // When I echo $this->following_list, I get both Greg(1,2,3,4,99) and Jenny(5,6,99,7)'s following lists

         // Here, I am turning following list into array by using explode
         $this->following_array = explode(",", $this->following_list);
            foreach($this->following_array as $key => $value){
            if($value == $this->myid){

                // Removing Mike(99)'s id number from Greg and Jenny's following lists
                unset($this->following_array[$key]);

                // Add back commas, which will then become string
                $this->new_following_list = implode(",", $this->_following_array);
                // When I echo $this->new_following_list, I get both Greg(1,2,3,4) and Jenny(5,6,7)'s new list without Mike(99)'s id number 

// My problem starts here. I was able to remove Mike's id number from Greg and Jenny's lists. But I am having a trouble updating Greg and Jenny's following lists with new following lists.  

            // The update query below does not work...
            $query = "UPDATE 'mytable' SET 'following_list' = $this->new_following_list WHERE 'id' IN ($this->follower_list)";
            $result = $this->dbc->query($query);
        } // End of if($value == $this->myid)
        } // End of foreach($this->following_array as $key => $value)
    }
    } 
} // End of function
4

2 回答 2

3

这将无法正确扩展。最好像这样规范化您的数据模型：

下列的

user_id | following_user_id
---------------------------
     77 |                 1
     77 |                 2
     77 |                 3
     77 |                 4
     77 |                99
     88 |                 5
     88 |                 6
     88 |                 7
     88 |                99

并添加两个索引：

  • UNIQUE(user_id, following_user_id)
  • INDEX(following_user_id)

要获得 99 的关注者：

SELECT * FROM following WHERE following_user_id=99;

看看谁 77 关注：

SELECT * FROM following WHERE user_id=77;
于 2012-06-01T08:41:21.843 回答
1

我认为您的数据库设置不是最佳的。将逗号分隔的值存储在一个字段中，为绑定表和一些规范化尖叫！

您应该将逗号分隔值列表设置为表/关系，例如：

followTable:/  user_id | follows

删除 mike 的 id 就很简单：

DELETE FROM followTable WHERE follows = 99 OR user_id = 99

后者确保迈克和他的追随者之间的链接也被删除。

于 2012-06-01T08:41:19.147 回答