Question

我有以下文件：

public class Post
{
   public string Id {get;set;}
   public string BlogId {get;set;}
   public string AuthorId {get;set;}
   public string Content {get;set;}
}

public class Blog
{
  public string Id {get;set;}
  public string Language {get;set;}
}

我需要创建一个索引，以便我可以用特定语言计算博客中每个用户的帖子数（所以我想过滤Blog.Language属性）。

首先我认为multimap / reduce索引是一种方法：

AddMap<Post>((posts) => from post in posts
                        select new 
                        {
                          UserId = post.AuthorId,
                          Count = 1,
                          Language = Language.None
                        });
AddMap<Blog>((blogs) => from blog in blogs
                        select new
                        {
                          UserId = null,
                          Count = 0,
                          Language = blog.Language 
                        });

但是你看到Blog中没有指定UserId属性，所以我认为我不能让Reduce部分工作（因为我要减少UserId属性）。

Answer 1

据我了解，您不需要索引中的博客，而是他们的语言：

AddMap<Post>((posts) => from post in posts
                        select new 
                        {
                          UserId = post.AuthorId,
                          Count = 1,
                          Language = LoadDocument<Blog>(post.BlogId).Language
                        });

然后按UserId和Language缩小：

Reduce = results => from result in results 
                    group result by new { result.UserId, result.Language }
                    into g 
                    select new { 
                        UserId = g.Key.UserId, 
                        Count = g.Sum(x => x.Count),
                        Language = g.Key.Language
                    };

RavenDb在没有共同属性的情况下多重映射/减少索引

1 个答案: