Question

我想知道在给定条件的情况下是否存在用于销毁has_many关联的rails方法。的买方

class Buyer < ActiveRecord::Base
  has_many :phones, as: :phoneable, dependent: :destroy, class_name: 'Telephone'
end

电话

class Telephone < ActiveRecord::Base
  belongs_to :phoneable, polymorphic: true
end

我想通过电话加入买家并销毁所有电话where('buyers.tel = telephones.number')。编写此查询的最佳方式是什么？

Answer 1

如果你只处理1 Buyer条记录：

buyer = Buyer.first
buyer.phones.where('number = ?', buyer.tel).destroy_all

如果适用于所有Buyers：

# XXX this will select all buyers you want but in your case you want to destroy the phones not the buyers so we need the reverse one check next:
Buyer.joins(:phones).where("buyers.tel = telephones.number")

# but this one will as we need the reverse relation:
Telephone.where("phoneable_type = 'Buyer' and buyers.tel = telephones.number").includes(:phoneable)

请注意，我们添加phoneable_type = 'Buyer'条件，因为您具有多态关系，而您只需要为Buyer创建的条件

Rails - 破坏联接表＆＃39;关联

1 个答案: