Question

所以我有这个：

User:
 has_many: subscriptions

Subscription:
 belongs_to: user
 has_many: payments

Payment:
 belongs_to: subscription

如果我有付款ID，我该如何找到用户？

Answer 1

正如尼克所说，Payment.find(id).subscription.user会很有效。如果您经常这样做，我建议您同时添加has_one :through关系。

class Payment < ApplicationRecord
  belongs_to :subscription
  has_one :user, through: :subscription
end

然后你可以直接引用Payment.find(id).user！

Answer 2

如果您声明从付款到用户的间接关联，您可以直接获取：

class User < ApplicationRecord
  has_many :subscriptions
  has_many :payments, through: :subscriptions
end

clas Subscription < ApplicationRecord
  belongs_to :user
  has_many :payments
end

class Payment < ApplicationRecord
  belongs_to :subscription
  has_one :user, through: :subscription  
end

user = User.joins(:payments).where(payments: { id: [id] }).first
# or
payment = Payment.eager_load(:user).find(id)
user = payment.user

Ruby：如何找到哪个用户所属的付款有很多关系

2 个答案: