Question

我在Rails 4项目中有以下数据库关系

class Hat < ActiveRecord::Base
  belongs_to :sale, as: product
end

class Shoe < ActiveRecord::Base
  belongs_to :sale, as: product
end

class Sale < ActiveRecord::Base
  has_many :products, polymorphic: true

  scope :hats, -> { ??? }
  scope :shoes, -> { ??? }
end

鉴于@sale对象，我如何获得属于特定模型的所有产品，例如Hat或Shoe？

Answer 1

您的表格中应该有product_type（有关详情，请参阅the guides），因此我会对此进行查询：

scope :hats, -> { where(product_type: Hat.name) }
# Not sure that this `Hat.class.name` is the actual value in the table, 
# so you might aswell check in your DB what's the correct value.

用于分隔多态关系的范围

1 个答案: