用mongoid反規格化

Question

用mongoid和Rails去規範化的最好方法是什麼？

使用「嵌入式」關係似乎不起作用（或僅用於嵌入整個原始文檔）。

我現在的解決方案商店和檢索非規範化的屬性作爲OrderedHash：

collection.update({_id: id, ...}, {..., denormalized: {_id: other.id, _type: other._type, a: other.a, b: other.b}} 

def denormalized 
    Mongoid::Factory.build(attributes[:denormalized]["_type"], attributes[:denormalized]) 
end 

編輯：我要指出，我沒有嘗試https://github.com/logandk/mongoid_denormalize

它變平的非規範化的屬性（在本例下面，它將存儲author_name而不是author：{name：「value」}，它不支持多個非規範化關係（例如authors：[{name：「First Co-Author」，_id：1}，{name ：「Second Co-Author」，_id：2}]）

編輯：請求了一個例子。

class User # this class uses STI so _type field is important 
    include Mongoid::Document 

    field :name # this is the field I want to de-normalize to where Users are referenced 

    def write_book 
    Book.create!({title: "Some Text", author: {_id: self.id, _type: self._type, name: self.name}) 
    end 
end 

class Book 
    include Mongoid::Document 

    field :title 

    # embeds_one :author, polymorphic: true 
    # tried this but it doesn't seem to be correct usage... it sort of works but 
    # I run into problems with cycles and infinite loops when used extensively 
    # because (I think) of how mongoid works internally, expecting embeds_one 
    # to mean something different 

    def author 
    Mongoid::Factory.build(attributes[:author]["_type"], attributes[:author]) 
    end 
end 

正確的解決方案會有ActiveModel方法，如new_record？工作以及* _path和* _url路由助手。

Answer 1

這會將用戶存儲爲書中的嵌入式作者文檔。

class User 
    include Mongoid::Document 
end 

#instead of the write book method, you could just do this: 
book = Book.create(title: "Old Man And The Sea", users: [user]) 

class Book 
    include Mongoid::Document 

    embeds_many :authors 

    field :title 

    def users=(users) 
    users.each do |user| 
     authors.build(user: user, name: user.name) 
    end 
    end 
end 

class Author 
    include Mongoid::Document 

    embedded_in :book 
    referenced_in :user 

    field :name 
end