三个模型之间的关联

Question

在这个我正在努力做的工作协会中度过美好的一天，使用 nested_form

#_form.html.erb in post
<%= f.fields_for :addresses do |address| %>
  <% address.association :state  %>
<% end %>

class Post < ApplicationRecord
  has_many :addresses, as: :addressable, dependent: :destroy
  accepts_nested_attributes_for :addresses, allow_destroy: true
end



class Address < ApplicationRecord
  belongs_to :states
  belongs_to :addressable, :polymorphic => true
end

class State < ApplicationRecord
  has_many :addresses  
end

打印错误：关联：未找到状态！！！帮帮我！

Answer 1

更改您的 State class 代码。

class Address < ApplicationRecord
  belongs_to :state
  belongs_to :addressable, :polymorphic => true
end

您使用了 states 而不是 state。因此，您遇到了错误。

Answer 2

来自docs：

class Book < ApplicationRecord
  belongs_to :author
end
belongs_to associations must use the singular term. If you used the pluralized form in the above example for the author association in the Book model, you would be told that there was an "uninitialized constant Book::Authors". This is because Rails automatically infers the class name from the association name. If the association name is wrongly pluralized, then the inferred class will be wrongly pluralized too.

所以你必须替换行：

belongs_to :states

和

belongs_to :state

三个模型之间的关联

association between three models

ruby-on-rails

associations

models