如何在 Rails3 中对关联关系使用 unscoped? [英] How to use unscoped on associated relations in Rails3?

问题描述

由于信息安全限制，我对产品有一个默认范围.

I have a default scope on products due to information security constraints.

class Product < ActiveRecord::Base
  has_many :photos

  default_scope where('visible = 1')
end

但是，在我关联的照片模型中，我还必须找到不应该显示的产品.

In my associated Photo model, however, I also have to find products that should not be visible.

class Photo < ActiveRecord::Base
  belongs_to :product
end

my_photo.product

在其他情况下，我可以按顺序使用 unscoped绕过default_scope，例如在 Product.unscoped.find_by_title('abc') 中.但是:

In other cases, I can use unscoped in order to bypass the default_scope, e.g. in Product.unscoped.find_by_title('abc'). However:

如何在使用记录关联时移除范围?

my_photo.unscoped.product 没有意义，因为 my_photo 没有名为 unscoped 的方法.my_photo.product.unscoped 也没有意义，因为 my_photo.product 可能已经为零.

my_photo.unscoped.product does not make sense as my_photo does not have a method called unscoped. Neither does my_photo.product.unscoped make sense as my_photo.product may already be nil.

推荐答案

哦.我骗了自己.认为以下方法行不通……但确实如此:

Oh. I fooled myself. Thought the following would not work... but it does:

Product.unscoped do
  my_photo.product
end

请注意，您必须使用应该绕过的 default_scope 在模型上调用 unscoped.

Notice that you have to call unscoped on the model with the default_scope that should be bypassed.

此外，必须尊重继承.如果您有 class InsuranceProduct 和 类 FinancialProduct 和 Product 中的 default_scope，以下两种组合都可以使用:

Also, inheritance has to be respected. If you have class InsuranceProduct < Productand class FinancialProduct < Product and a default_scope in Product, all of the following two combinations will work:

InsuranceProduct.unscoped do
  my_record.insurance_products
end

FinancialProduct.unscoped do
  my_record.financial_products
end

Product.unscoped do
  my_record.products
end

但是，尽管范围是在 Product 中定义的，但以下 将不起作用:

However, the following will not work although the scope is defined in Product:

Product.unscoped do
  my_record.financial_products
end

我想这是 Ruby/Rails 中 STI 的另一个怪癖.

I guess that's another quirk of STI in Ruby / Rails.

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