ActiveRecord :inverse_of 不适用于 has_many :through 在创建时的连接模型上 [英] ActiveRecord :inverse_of does not work on has_many :through on the join model on create

问题描述

我无法让 inverse_of 在创建时处理连接模型.我不确定这是一个错误还是只是没有实现.我有以下型号:

课程挑战:group_challengeshas_many :group_challenges, :inverse_of =>:挑战attr_accessor :contact_ids结尾class GroupChallenge :group_challenges所属:组，:inverse_of =>:group_challengesbefore_save :check_challengedef check_challengeRails.logger.debug("challenge.contact_ids: #{challenge.contact_ids}")结尾结尾班级组:group_challengeshas_many :group_challenges, :inverse_of =>:团体结尾

contact_ids 是我的 challenge 的虚拟属性，我想在创建关联时在 group_challenges 模型中访问这些.我无法让它工作.举个例子:

challenge = Challenge.new :groups =>Group.all, :contact_ids =>[1,2,3]# 日志输出 =>Challenge.contact_ids: []

但是 inverse_of 在模型重新加载时确实有效

challenge.reloadChallenge.group_challenges.first.challenge.contact_ids# 日志输出 =>Challenge.contact_ids: [1,2,3]

有谁知道这只是 inverse_of 的设计限制还是实现中的错误?

解决方案

根据 活动记录 api 3.2.../p>

I can't get inverse_of to work on join models on creation. I'm not sure if this is a bug or just not implemented as such. I have the following models:

class Challenge < ActiveRecord::Base
  has_many :groups, :through => :group_challenges
  has_many :group_challenges, :inverse_of => :challenge

  attr_accessor :contact_ids
end

class GroupChallenge < ActiveRecord::Base
  belongs_to :challenge, :inverse_of => :group_challenges
  belongs_to :group, :inverse_of => :group_challenges

  before_save :check_challenge

  def check_challenge
    Rails.logger.debug("challenge.contact_ids: #{challenge.contact_ids}")
  end
end

class Group < ActiveRecord::Base
  has_many :challenges, :through => :group_challenges
  has_many :group_challenges, :inverse_of => :group
end

contact_ids is a virtual attribute of my challenge, and I'd like to access these in the group_challenges model when that association is created. I can't get it to work. Here's an example:

challenge = Challenge.new :groups => Group.all, :contact_ids => [1,2,3]
# log output => challenge.contact_ids: []

However inverse_of does work when the models are reloaded

challenge.reload
challenge.group_challenges.first.challenge.contact_ids
# log output => challenge.contact_ids: [1,2,3]

Does anyone know if this is just a design limitation of inverse_of or rather a bug in the implementation?

解决方案

As per the active record api 3.2.1: "Currently :inverse_of supports has_one and has_many (but not the :through variants) associations. It also supplies inverse support for belongs_to associations where the inverse is a has_one and it’s not a polymorphic."

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