Question

我正在尝试计算交易总成本的多少。并且要测试我正在运行Transaction.last.calculate_total_payment，它返回BigDecimal这是我想要的，但之后没有任何属性在实例上更新。我做错了什么？

class Transaction < ActiveRecord::Base
    has_one :auction
    has_one :bid
    belongs_to :inventory_part      
    TIER0 = 0
    TIER1 = 5_000
    TIER2 = 50_000
    TIER3 = 500_000
    TIER4 = 1_000_000
.
.
.
.

    def calculate_total_payment
    part = self.bid.part_price

    self.tax = part * self.tax_rate

    if self.bid.tx.shipping_account
        self.final_shipping_cost = 0 
    else # testing purposes
        self.final_shipping_cost = self.bid.est_shipping_cost
    end
    price_before_fees = part + self.tax + self.final_shipping_cost

    if price_before_fees < TIER1 #5,000
      self.bid_aero_fee = price_before_fees * 0.025
      self.armor_fee = price_before_fees * 0.015
    elsif price_before_fees < TIER2 #50,000
      self.bid_aero_fee = (price_before_fees - TIER1) * 0.015 + 125
      self.armor_fee = (price_before_fees - TIER1) * 0.01 + 75
    elsif price_before_fees < TIER3 #500,000
      self.bid_aero_fee = (price_before_fees - TIER2) * 0.0125 + 800
      self.armor_fee = (price_before_fees - TIER2) * 0.0075 + 525
    elsif price_before_fees < TIER4 #1,000,000
      self.bid_aero_fee = (price_before_fees - TIER3) * 0.0075 + 6425
      self.armor_fee = (price_before_fees - TIER3) * 0.005 + 3900
    else # anything over a million
        self.bid_aero_fee = (price_before_fees - TIER4) * 0.0075 + 10175
        self.armor_fee = (price_before_fees - TIER4) * 0.0035 + 6400
    end

    self.total_fee = self.armor_fee + self.bid_aero_fee
    self.total_amount = price_before_fees + self.total_fee
  end
end

Answer 1

您永远不会在save方法中调用calculate_total_payment。您需要明确保存对象，以便将其保留在数据库中。

Answer 2

如果要在数据库中保持更改，最后应调用save!。如果没有这个，它将修改对象（因此重新加载再次获取对象后更改将消失）。

rails将属性分配给实例

2 个答案: