加入和合并父模型时出现 ActiveModel::MissingAttributeError？ [复制]

Question

我正在使用Geocoder 和Will Paginate。我正在尝试比较用户地址和孩子妈妈地址之间的距离。这是我的模型：

class User
 has_many :kids
 geocoded_by :address
end

class Kid
  belongs_to :mom
  belongs_to :dad
end

class Mom
  has_many :kids
  has_many :dads, through: :kids
  geocoded_by :address
end

class Dad
  has_many :kids
  has_many :moms, through: :kids
end

比我如何尝试让它发挥作用：

class ApplicationController
  before_filter :set_user_location

  private

  def set_user_location
    if signed_in?
      @user_location = current_user.address
    end
  end
end

class DadsController

def show
  @dad = Dad.find(params[:id])
  @kids = @dad.kids.joins(:mom).merge(Mom.near(@user_location, 100)).order(name: :asc, created_at: :desc).paginate(page: params[:page], per_page: 25)
end

现在有了所有这些。我遇到了错误：

ActiveModel::MissingAttributeError - missing attribute: birthday:
  activerecord (4.0.2) lib/active_record/attribute_methods/read.rb:95:in `block (2 levels) in read_attribute'
  activerecord (4.0.2) lib/active_record/attribute_methods/read.rb:94:in `fetch'
  activerecord (4.0.2) lib/active_record/attribute_methods/read.rb:94:in `block in read_attribute'
  activerecord (4.0.2) lib/active_record/attribute_methods/read.rb:84:in `fetch'
  activerecord (4.0.2) lib/active_record/attribute_methods/read.rb:84:in `read_attribute'
  activerecord (4.0.2) lib/active_record/attribute_methods/read.rb:59:in `__temp__57e69647'
  app/views/dads/show.html.erb:27:in `block in _app_views_dads_show_html_erb__397094631_92677670'
  activerecord (4.0.2) lib/active_record/relation/delegation.rb:13:in `each'
  activerecord (4.0.2) lib/active_record/relation/delegation.rb:13:in `each'
............

如果我从循环中删除 kid.birthday，它会说下一个属性是问题，直到我的 dads/show.html.erb 上没有任何属性。

<% @kids.each do |kid| %>
   <%= kid.birthday %>
   <%= kid.name %>
   <% if kid.upkeep.present? %>
     <%= kid.upkeep %>
     <%= kid.upkeep_size %> 
   <% end %>      
   <%= kid.age %>
   <%= kid.favorite_color %>
<% end %>

我该如何解决这个问题？

Answer 1

我认为问题在于，当你这样做时，你会把孩子和妈妈结合起来：

.merge(Mom.near(@user_location, 100))

因此，除了 Kid 对象之外，@kids 还将包含 Mom 对象，而那些 Mom 对象不具有您期望的属性。您可以使用@kids.inspect 进行调试。