Question

我正在编制预订系统。我希望我的用户一次只能预订一个（或定义数量）的资源。但是，我不想删除＆＃34;过去＆＃34;保留我的数据库，因为它将用于开发票的目的。在创建预订时，我需要验证用户是否未超过其预留配额，这意味着不超过＆＃34; quota＆＃34;将来保留。

class User < ActiveRecord::Base
    has_many :reservations

    def active_reservations
        #maybe worth to rewrite with a "find"?
        my_list = []
        reservations.each do |reservation|
        if (not reservation.past?)
            my_list.push(reservation)
        end
        return my_list
    end

class Reservation < ActiveRecord::Base
    belongs_to :user
    validate :respect_user_quota
    def past?
        return (date < Date.now)

    def respect_user_quota
        if (user.active_reservations.count > user.quota)
            errors.add(:user, "User quota exceeded!")

这是实施此验证的正确方法吗？可能有什么问题（我从未看到错误信息）。是否应将配额验证移至用户类？

Answer 1

我会尝试更简单地执行此操作并将验证移至用户。

class User < ActiveRecord::Base
  has_many :reservations

  validate :reservation_quota
    if sum(reservations.active) > quota  # User.quota is implied here
      errors.add(:user, "User quota exceeded!")
    end

class Reservation < ActiveRecord::Base
  belongs_to :user
  def active
    active? 1 : 0  
     # If there's a boolean 'active' flag the ? method gets created automatically.    
     # This could be (reservation_date < Date.now)? ? 1 : 0 for you.
     # Using `(expression)? ? true : false` is using the Ternary operator. 
  end
end

ruby验证：根据时间限制一个对象的对象数量（has_many）

1 个答案: