为什么 ActiveRecord 不够聪明，无法知道父亲的 object_id 应该等于其孩子的父级的 object_id? [英] Why is ActiveRecord not smart enough to know that the object_id of the father should be equal to the object_id of the parent of its children?

问题描述

  @father = Hierarchy.find(:first, :conditions => ['label = ?', 'father'])

  @father.children.each do |child|
    puts @father.object_id == child.parent.object_id
  end

我原以为这里的结果都是true.

I would have thought the results here would be all true.

相反，它们都是false.

为什么 ActiveRecord 以这种方式工作，而不是识别出这些是相同的 Ruby 对象?

Why does ActiveRecord work this way instead of recognizing that these are the same Ruby objects?

推荐答案

对于那些在被问到这个问题后几年偶然发现的人(像我一样！)，请查看 https://stackoverflow.com/a/4116397/1000655.

For anyone who stumbles across this years after it was asked (like me!), check out https://stackoverflow.com/a/4116397/1000655.

建议使用 :inverse_of 来建立双向关联.我真希望我过去没有浏览过那么多次文档！

It suggests using :inverse_of to set up Bi-directional associations. I wish I hadn't skimmed that bit of the documentation so many times in the past!

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