我今天遇到了一些麻烦,无法在盒子外面思考解决这个问题。
基本上我有一个名为Airplane的模型,它有很多付款。每笔付款可分为多个分期付款。 OK!
以下是信息:
Model Airplane
- has_many payments
- before_save :checks_if_everything_has_been_paid
Model Payment
- belongs_to airplane
- has_many installments
Model Installment
- belongs_to payment
所以,我想要做的是当分期付款的总和等于或大于飞机票价值时,Airplane.paid将为真。我正在使用before_save“checks_if_everything_has_been_paid。但它仅在飞机领域发生变化时才有效。
如果付款和分期付款字段都有更改,我该如何运行此类?
我想检查每次更改分期付款或付款本身时付款是否完成。
谢谢!
答案 0 :(得分:2)
不是在Airplane模型上定义after save
回调,而是在after_add
关联上定义payments
回调。
class Airplane < ActiveRecord::Base
has_many :payments, after_add: :checks_if_everything_has_been_paid
def checks_if_everything_has_been_paid
# work some magic
end
end
更新:如果我正确理解您的数据模型,我认为以下可能是更好的方法。如果保存付款或分期付款,它将触发飞机检查全额付款:
class Airplane < ActiveRecord::Base
has_many :payments
has_many :installments, through: :payments
def check_for_full_payment
# work some magic
end
end
class Payment < ActiveRecord::Base
belongs_to :airplane
has_many :installments
after_save :trigger_full_payment_check
def trigger_payments_check
airplane.check_for_full_payment
end
end
class Installment < ActiveRecord::Base
belongs_to :payment
delegate :airplane, to: :payment
after_save :trigger_full_payment_check
def trigger_payments_check
airplane.check_for_full_payment
end
end
这种方法的好处是付款和分期付款中的逻辑是相同的,因此您可以将其提取到模块中:
module TriggerFullPaymentCheck
def self.included(base)
base.after_save :trigger_full_payment_check
end
def trigger_payments_check
airplane.check_for_full_payment
end
end
class Airplane < ActiveRecord::Base
has_many :payments
has_many :installments, through: :payments
def check_for_full_payment
# work some magic
end
end
class Payment < ActiveRecord::Base
include TriggerFullPaymentCheck
belongs_to :airplane
has_many :installments
end
class Installment < ActiveRecord::Base
include TriggerFullPaymentCheck
belongs_to :payment
delegate :airplane, to: :payment
end
答案 1 :(得分:0)
您可以尝试在belongs_to
关联上设置:autosave
。如果可行的话,那就是一个聪明的解决方案:)。
更好的选择可能是创建一个after_save
挂钩,要求飞机自行检查。
class Airplane
has_many :payments
def check_for_paid
# use payments(true) to force the association to reload
if payments(true).all?(&:paid?)
paid = true
save
end
end
end
class Payment
# associations
def paid?
installments(true).all?(&:paid?)
end
end
class Installment
after_save :check_for_paid
def check_for_paid
payment.airplane.check_for_paid
end
end
这样可以更清楚地了解发生了什么以及为什么。但另一方肯定会更聪明。