Question

我的应用程序中有一个多态关联，用于跟踪应用程序中的订单。我希望能够查询Meal这个模型:orderable，但是由于某种原因，在添加关联后，对:valid?的调用会引发错误。

class Order < ApplicationRecord
  belongs_to :order_status
  belongs_to :client
  has_many :order_items
  has_many :orderables, through: :order_items, source: :orderable, source_type: 'Meal'
end

class OrderItem < ApplicationRecord
  belongs_to :order
  belongs_to :meal, -> { where( order_items: { orderable_type: 'Meal' } ).includes(:meal) }, foreign_key: 'orderable_id'

  belongs_to :orderable, polymorphic: true

  validates :quantity, presence: true, numericality: { only_integer: true, greater_than: 0 }
  validate :order_present
  validate :item_present

  scope :are_veggies, -> { includes( :meal ).where( :meals => { type_of: 'veggie' }) }
  scope :are_meals, -> { includes( :meal ).where.not( :meals => { type_of: 'veggie' }) }

    private

  def item_present
    if orderable.present? and !orderable.active
      errors.add(:orderable, "Selected item is not available.")
    end
  end

  def order_present
    if order.nil?
      errors.add(:order, "is not a valid order.")
    end
  end
end

class Meal < ApplicationRecord
    extend FriendlyId
    friendly_id :name, use: :slugged

    has_many :tags, as: :taggable
    has_many :order_items, as: :orderable

    validates_presence_of :name, :type_of

    default_scope { where(active: true) }
end

所有查询均正常运行，我可以致电Order.find(x).meals。我可以打电话给Order.find(x).order_items.are_meals。

但是当我尝试致电OrderItem.find(x).valid?时，我看到一个错误：ActiveRecord::ConfigurationError: Can't join 'Meal' to association named 'meal'; perhaps you misspelled it?。知道是什么原因造成的吗？

Answer 1

我输入了错误的模型：

# This
belongs_to :meal, -> { where( order_items: { orderable_type: 'Meal' } ).includes(:meal) }, foreign_key: 'orderable_id'

# Should have been
belongs_to :meal, -> { where( order_items: { orderable_type: 'Meal' } ).includes(:order_items) }, foreign_key: 'orderable_id'

查询导致有效性错误的多态关联

1 个答案: