Question

我有两张桌子 - 用户和关注。下表定义了两个用户，即跟随的用户和所遵循的用户。想想像Twitter一样的想法。

我想做一个推荐的人物页面。这将建议追随者的追随者按其感知的相关性顺序。

所以如果我有人A。

他跟随B和C人员

如果人B和C都跟随人D，而人B跟随人E.人D应该比人E具有更高的相关性，等等。

有人可以帮我构建一个能够以最快的方式执行此操作的查询。考虑到有很多粉丝的人的潜力。

最终，我想要一个页面说 - 看看这些人：约翰跟随着你跟随的4个人。

我的表格样本

public class User 
{
    public long UserId { get; set; }

    public string Name { get; set; }
}

public class Follow 
{
    public long FollowId { get; set; }

    public User Follower { get; set; }
    public User Following { get; set; }
}

编辑 - 基于Patrick Mcdonalds回答的当前查询

var query = from follow in db.Follows
            where follow.WhoIsFollowing == mee
            let friend = follow.WhoTheyAreFollowing
            from friendOfFriend in db.Follows
            where friendOfFriend.WhoIsFollowing == friend
            group friendOfFriend by friendOfFriend.WhoTheyAreFollowing into g
            where g.Key != mee
            select new { UserId = g.Key, Count = g.Count() };

Answer 1

您可以从以下内容开始：

List<Follow> followers = new List<Follow>();

var query = from follow in followers
            where follow.Follower.UserId == 1
            let friend = follow.Following
            from friendOfFriend in followers
            where friendOfFriend.Follower.UserId == friend.UserId
            group friendOfFriend by friendOfFriend.Following.UserId into g
            select new { UserId = g.Key, Count = g.Count() };

var suggestionList = query.OrderByDescending(f => f.Count).ToList();

然后你应该过滤掉你已经关注的用户，也可以过滤自己。（如果你关注的每个人都跟着你回来，你会出现在建议的顶部）

修改

尝试使用以下内容过滤掉自己和关注者：

int me = 1; var friends = from follow in followers where follow.Follower.UserId == me select follow.Following.UserId; var query = from friend in friends from friendOfFriend in followers where friendOfFriend.Following.UserId != me where !friends.Contains(friendOfFriend.Following.UserId) where friendOfFriend.Follower.UserId == friend group friendOfFriend by friendOfFriend.Following.UserId into g select new { UserId = g.Key, Count = g.Count() }; var suggestionList = query.OrderByDescending(f => f.Count).ToList();

Answer 2

根据您的存储机制，您无需使用“关注”作为中间人。

考虑这个结构：

public class User 
{
    public long UserId { get; set; }
    public string Name { get; set; }
    public List<User> Following { get; set;}
}

现在，您可以轻松检索此人关注的对象。

假设您有一个List<User> userList并且想要搜索它们以查找谁在关注用户ID

var user5 = userList.Where(x => x.UserID == 5).FirstOrDefault();
var usersFollowingUserID5 = userList.Where(x => x.Following.Contains(user5));

Answer 3

为了与您当前的结构保持一致，您可以这样做：

var john = userList.Where(x=> x.Name == "John").FirstOrDefault();
var peopleFollowingJohn = followingList.Where(x => x.Following ==  john);
var peopleJohnIsFollowing = followingList.Where(x => x.Follower ==  john);

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3 个答案: