与同型号的多个关联多态性协会 [英] Polymorphic Association with multiple associations on the same model

问题描述

我略有困惑我有一个多态关联。我需要一个第三模型有一个头形象，和许多图像，但我希望有一个单一的图像模型。为了使事情更加混乱，图像模型是多态（允许其他资源有许多图像）。

I'm slightly confused about a polymorphic association I've got. I need an Article model to have a header image, and many images, but I want to have a single Image model. To make matters even more confusing, the Image model is polymorphic (to allow other resources to have many images).

我用在我的文章模型这种关联：

I'm using this association in my Article model:

class Article < ActiveRecord::Base
  has_one :header_image, :as => :imageable
  has_many :images, :as => :imageable
end

这可能吗？谢谢你。

Is this possible? Thanks.

推荐答案

是的。这是完全可能的。

Yep. That's totally possible.

您可能需要指定 header_image 类的名称，因为它无法推断。包括：依赖=＆GT; ：破坏太，以确保如果该制品被去除的图像被破坏

You might need to specify the class name for header_image, as it can't be inferred. Include :dependent => :destroy too, to ensure that the images are destroyed if the article is removed

class Article < ActiveRecord::Base
  has_one :header_image, :as => :imageable, :class_name => 'Image', :dependent => :destroy
  has_many :images, :as => :imageable, :dependent => :destroy
end

然后在另一端...

then on the other end...

class Image < ActiveRecord::Base
  belongs_to :imageable, :polymorphic => true
end

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