Question

我有3个型号如下：

class Kick < ActiveRecord::Base
 has_many :offs
 has_many :retailers, :through => :off
end

class Retailer < ActiveRecord::Base
 has_many :offs
 has_many :kicks, :through => :off
end

class Off < ActiveRecord::Base
 belongs_to :kicks
 belongs_to :retailers
end

我正试图在我的'show Kick view'中显示零售商的名称，如下所示：

  <% @kick.off.each do|off| %>
    <%= off.name %>
    <%= off.retailers.name %>
  <% end %>

Off.name显示正常，但我似乎无法从此视图中索引零售商的名称。我错过了什么？

错误：

undefined method `name' for nil:NilClass

Answer 1

class Kick < ActiveRecord::Base
 has_many :offs
 has_many :retailers, :through => :offs
end

class Retailer < ActiveRecord::Base
 has_many :offs
 has_many :kicks, :through => :offs
end

class Off < ActiveRecord::Base
 belongs_to :kick
 belongs_to :retailer
end


@kick = Kick.includes(:retailers => :offs).where('kicks.id' => 1).select('retailers.name, kicks.*')

Answer 2

hdfs dfs -put

还要确保在db

中正确索引模型

Answer 3

在视图中，它应为kick.offs而不是kick.off

<% @kick.offs.each do|off| %>
    <%= off.name %>
    <%= off.retailers.name %>
  <% end %>

在Rails 4中显示嵌套关联

3 个答案: