ruby-on-rails – 带有“外键”的Mongoid

发布时间：2020-12-17 03:00:34 所属栏目：百科来源：网络整理

导读：作为 mongodb的资深人士,我创建了以下结构： User: { name: str,email: ... }Gift: { # author and receiver refer to User objects obviously author: object_id(...),receiver: object_id(...),name: str ... } 我想在mongoid中正确映射这个： class User

作为 mongodb的资深人士,我创建了以下结构：

User: { 
  name: str,email: ... 
}

Gift: { 
  # author and receiver refer to User objects obviously
  author: object_id(...),receiver: object_id(...),name: str 
  ... 
}

我想在mongoid中正确映射这个：

class User 
  include Mongoid::Document

  has_many :gifts
end

class Gift 
  include Mongoid::Document

  belongs_to :user
end

但是,映射不正确. g = Gift.first; g.author未定义.我该如何进行参考？

从技术上讲,它是：

User <--- 1: N via author---> Gift <--- N:1 via receiver---> User

(意思是用户可以是许多礼物的作者,并且用户可以是许多礼物的接收者,但是礼物可以只有1个作者和接收者).

Plz帮忙!!!

解决方法

如果Gift看起来像这样,你可能会对Rails有更好的运气：

Gift: { 
  # author and receiver refer to User objects obviously
  author_id: object_id(...),receiver_id: object_id(...),name: str 
  ... 
}

然后,将：foreign_key添加到Gift：

class Gift 
  include Mongoid::Document

  belongs_to :user,:foreign_key => 'author_id'
end

（编辑：李大同）

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