Rails 3:如何验证 A <B 其中 A 和 B 都是模型属性? [英] Rails 3: How to validate that A &lt; B where A and B are both model attributes?

问题描述

我想验证 customer_price >= my_price.我尝试了以下方法:

I would like to validate that customer_price >= my_price. I tried the following:

class Product < ActiveRecord::Base
  attr_accessor :my_price
  validates_numericality_of :customer_price, :greater_than_or_equal_to => my_price
  ...
end

(customer_price 是数据库中 Products 表中的一列，而 my_price 不是.)

(customer_price is a column in the Products table in the database, while my_price isn't.)

结果如下:

NameError in ProductsController#index
undefined local variable or method `my_price' for #<Class:0x313b648>

在 Rails 3 中执行此操作的正确方法是什么?

What is the right way to do this in Rails 3 ?

推荐答案

创建自定义验证器:

validate :price_is_less_than_total

# other model methods

private

  def price_is_less_than_total
    errors.add(:price, "should be less than total") if price > total
  end

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