訪問Mongoid中的父子屬性

Question

我有兩個類，即Person和Language。每個語言具有創建者和更新者均來自Person類。我想通過子查詢父代的屬性，反之亦然。

Person類

class Person 
    include Mongoid::Document 
    field :first_name, type: String 
    field :last_name, type: String 

    has_many :created_languages, class_name: 'Language', inverse_of: :created_by, foreign_key: 'created_by_id', autosave: true 
    accepts_nested_attributes_for :created_languages 

    has_many :updated_languages, class_name: 'Language', inverse_of: :updated_by, foreign_key: 'updated_by_id', autosave: true 
    accepts_nested_attributes_for :updated_languages 
end 

語言類

class Language 
    include Mongoid::Document 

    field :content, type: String 

    belongs_to :created_by, class_name: 'Person', inverse_of: :created_languages, foreign_key: :created_by_id, autosave: true 
    accepts_nested_attributes_for :created_by 

    belongs_to :updated_by, class_name: 'Person', inverse_of: :updated_languages, foreign_key: :updated_by_id, autosave: true 
    accepts_nested_attributes_for :updated_by 
end 

我想在我的Rails應用程序來查詢如下：即在Rails的控制檯：

ruby 2.0.0p451 > a = Person.create!(first_name: "Marco", last_name:"Reus") 
ruby 2.0.0p451 > b = Language.create!(content: "German", created_by_id: a.id, updated_by_id: a.id) 
ruby 2.0.0p451 > a.created_languages (now works) 
ruby 2.0.0p451 > a.updated_languages (now works) 
ruby 2.0.0p451 > b.created_by (now works) 
ruby 2.0.0p451 > b.updated_by (now works) 

我用接收下面的錯誤。通過上面的代碼，它被解決了。

Mongoid ::錯誤:: AmbiguousRelationship：
問題：曖昧關係：created_languages，：對人定義updated_languages。

摘要：當Mongoid嘗試在內存中設置關係的逆文檔時，它需要知道它屬於哪個關係。當設置：updated_by時，Mongoid查找匹配關係類Language，但找到了可能匹配的倍數：：created_languages，：updated_languages。

Resolution：關於語言updated_by關係，您必須添加一個：inverse_of選項來指定與Person相反的：updated_by的確切關係。

Answer 1

你還應該包括inverse_of爲所有這些爲這樣：

has_many :created_languages, class_name: 'Language', :inverse_of => :created_by 

belongs_to :created_by, class_name: 'Person', :inverse_of => :created_languages 

希望它能幫助。