Rails -在父级被销毁时删除has_many关系

Question

我有三个模特

HiringTag

class HiringTag < ActiveRecord::Base
  attr_accessible :name, :staffroom_id
  validates :name, presence: true

  has_many :hiring_tag_applications
  has_many :job_applications, through: :hiring_tag_applications

  after_destroy { |application|
    HiringTagApplication.destroy(application.job_applications.pluck(:job_application_id))
end

HiringTagApplication

class HiringTagApplication < ActiveRecord::Base
  belongs_to :hiring_tag, dependent: :destroy
  belongs_to :job_application
end

JobApplication

class JobApplication < ActiveRecord::Base
  has_many :hiring_tag_applications
  has_many :hiring_tags, through: :hiring_tag_applications
end

我要做的是:当我销毁HiringTag或JobApplication时，我希望删除HiringTagApplication中的相关数据，因为您会注意到，在HiringTag中有一个after_destroy可以执行回调，但我得到的错误是：

找不到HiringTagApplication和id=96453

96453不是id of HiringTagApplication，但它是job_application_id

我如何纠正这一点，以便可以删除该记录？

Answer 1

不需要after_destroy，只需正确地使用dependent: :destroy：

class HiringTag < ActiveRecord::Base
  has_many :hiring_tag_applications, dependent: :destroy
end

和

class JobApplication < ActiveRecord::Base
  has_many :hiring_tag_applications, dependent: :destroy
end

&从关联表中删除它

class HiringTagApplication < ActiveRecord::Base
  belongs_to :hiring_tag
  belongs_to :job_application
end

现在，每当HiringTag或JobApplication被删除时，其关联的HiringTagApplication也将被删除。