Rails-模型關聯-用戶和產品-自定義方法

Question

我正在創建一個具有兩個主要模型的應用程序：用戶和產品。 用戶可以擁有許多產品作為所有者，也可以擁有許多產品作為借款人。 產品只有一個所有者，但可以有許多尋求者，包括借款人。 我直接將它們與擁有財產相關聯，但是對於借款財產，我創建了一個交易模型。 這三個看起來像這樣：

app / models / transaction.rb

class Transaction
# has a seeker_id:integer, a product_id:integer and a current:boolean

  before_save :check_current

# Associations
  belongs_to :seeker, class_name: "User", foreign_key: "seeker_id"
  belongs_to :product

# Methods
    def check_current
      if !self.borrowing_date.nil? && self.return_date.nil?
        self.current = true
      end
    end

end

一種產品有很多transactions ，但當時只能由一個seeker借用。 當產品是借來的，本次交易有borrowing_date是not nil和return_date是nil 。 然后， check_current方法將此transaction的current布爾值從false切換為true 。 該當前transaction的seeker被指定為borrower 。

app / models / user.rb

class User
    .
    .
    .
  has_many :owned_products, class_name: "Product", foreign_key: "owner_id", dependent: :destroy
  has_many :transactions, foreign_key: "seeker_id", dependend: :destroy
  has_many :requested_products, through: :transactions, source: :product
  has_many :active_transactions, -> { where current: true },
                                 class_name: 'Transaction',
                                 foreign_key: "seeker_id",
                                 dependent: :destroy

  has_many :borrowed_products, through: :active_transactions,
                               source: :product

    def requesting?(product)
      self.transactions.find_by(product_id: product.id)
    end

    def request!(product)
      self.transactions.create!(product_id: product.id)
    end

    def borrowing?(product)
      self.transactions.find_by(product_id: product.id, current: true)
    end  

    def borrowed_products
      self.transactions.where(current: :true).product
    end



end

app / models / products.rb

class Product
    .
    .
    .
  belongs_to :owner, class_name: "User", foreign_key: "owner_id"
  has_many :transactions, dependent: :destroy
  has_many :seekers, through: :transactions,
                       source: :seeker



    def borrowed?
      self.transactions.find_by(current: true)
    end

    def borrower
      self.transactions.find_by(current: true).seeker
    end
end

當我測試一些代碼時，其中五個測試失敗，類型相同，並且我不明白為什么：

describe User do

  before { @user = User.new(name: "Utilisateur de test",
                            email: "test@utilisateur.com",
                            password: "motdepasse",
                            password_confirmation: "motdepasse") }

  subject { @user }


  describe "requested product associations" do

    let(:lender) { FactoryGirl.create(:user) }
    let(:product) { FactoryGirl.create(:product, owner: lender) }
    before do
      @user.save
      @user.request!(product)
    end

    it { should be_requesting(product) }
    its(:requested_products) { should include(product) } # FAIL

    describe "when product is borrowed" do

      before do
        transaction = Transaction.find_by(product: product)
        transaction.update_attributes(borrowing_date: 1.day.ago)
        transaction.save
      end

      it { should be_borrowing(product) }
      its(:requested_products) { should_not include(product) } # FAIL
      its(:borrowed_products) { should include(product) } # FAIL


      describe "then returned" do

        before do
          transaction = Transaction.find_by(product: product)
          transaction.update_attributes(return_date: 1.hour.ago)
        end

        it { should_not be_borrowing(product) }
        its(:requested_products) { should_not include(product) } # FAIL
        its(:borrowed_products) { should_not include(product) } # FAIL
      end
    end
  end
end

這是錯誤消息：

1) User requested product associations requested_products 
   Failure/Error: its(:requested_products) { should include(product) }
   ActiveRecord::StatementInvalid:
     SQLite3::SQLException: ambiguous column name: created_at: SELECT  1 AS one FROM "products" INNER JOIN "transactions" ON "products"."id" = "transactions"."product_id" WHERE "transactions"."seeker_id" = ? AND "products"."id" = 1  ORDER BY created_at DESC LIMIT 1
   # ./spec/models/user_spec.rb:174:in `block (3 levels) in <top (required)>'

2) User requested product associations when product has been borrowed borrowed_products 
   Failure/Error: its(:borrowed_products) { should include(product) }
   ActiveRecord::StatementInvalid:
     SQLite3::SQLException: ambiguous column name: created_at: SELECT  1 AS one FROM "products" INNER JOIN "transactions" ON "products"."id" = "transactions"."product_id" WHERE "transactions"."seeker_id" = ? AND "transactions"."current" = 't' AND "products"."id" = 1  ORDER BY created_at DESC LIMIT 1
   # ./spec/models/user_spec.rb:185:in `block (4 levels) in <top (required)>'

3) User requested product associations when product has been borrowed requested_products 
   Failure/Error: its(:requested_products) { should_not include(product) }
   ActiveRecord::StatementInvalid:
     SQLite3::SQLException: ambiguous column name: created_at: SELECT  1 AS one FROM "products" INNER JOIN "transactions" ON "products"."id" = "transactions"."product_id" WHERE "transactions"."seeker_id" = ? AND "products"."id" = 1  ORDER BY created_at DESC LIMIT 1
   # ./spec/models/user_spec.rb:184:in `block (4 levels) in <top (required)>'

4) User requested product associations when product has been borrowed then returned requested_products 
   Failure/Error: its(:requested_products) { should_not include(product) }
   ActiveRecord::StatementInvalid:
     SQLite3::SQLException: ambiguous column name: created_at: SELECT  1 AS one FROM "products" INNER JOIN "transactions" ON "products"."id" = "transactions"."product_id" WHERE "transactions"."seeker_id" = ? AND "products"."id" = 1  ORDER BY created_at DESC LIMIT 1
   # ./spec/models/user_spec.rb:195:in `block (5 levels) in <top (required)>'

5) User requested product associations when product has been borrowed then returned borrowed_products 
   Failure/Error: its(:borrowed_products) { should_not include(product) }
   ActiveRecord::StatementInvalid:
     SQLite3::SQLException: ambiguous column name: created_at: SELECT  1 AS one FROM "products" INNER JOIN "transactions" ON "products"."id" = "transactions"."product_id" WHERE "transactions"."seeker_id" = ? AND "transactions"."current" = 't' AND "products"."id" = 1  ORDER BY created_at DESC LIMIT 1
   # ./spec/models/user_spec.rb:196:in `block (5 levels) in <top (required)>'

但是，當我在Rails控制台中手動運行一些測試時， user.borrowed_products和user.requested_products正常工作。 奇怪的 ？？？

Answer 1

對於第一次失敗的測試

def borrowed_products
      self.transactions.where(current: :true).product
 end

上面的方法檢查電流：true。 我看不到您在交易設置中設置屬性。

before do
  transaction = Transaction.find_by(product: product)
  transaction.update_attributes(borrowing_date: 1.day.ago) #Why are you setting borrowing date. How is borrowing date and current related?
  transaction.save
end

對於第二次測試。

request_products關聯是通過交易建立的。 您沒有設置交易。 是在您的工廠完成的嗎？

Answer 2

好的，我找到了！ Yippee-ki-yay！

錯誤消息告訴我created_at列不明確。 但為什么 ？ 因為created_at列和關聯的模型一樣多！ 因此，它與此有關。 但是created_at在我的代碼中出現了什么地方？

我檢查了我的app / models / transaction.rb ，我的app / models / user.rb和我的app / models / product.rb ，在最后一個模型中，我找到了這一行：

default_scope -> { order('created_at DESC') }

我改為那，只是嘗試：

default_scope -> { order('name DESC') }

而且一切都很好！

但是現在，如果我想通過created_at對其進行范圍划分，我不知道如何做到這一點:-p