在rails中包括没有关系的表

Question

我有控制器，我正在使用以下代码加载所有发票。

  def index
    @invoices = Invoice.includes(:customer).all
  end

我有以下发票和客户模型

class Invoice < ApplicationRecord
  belongs_to :customer

  delegate :name,
           :street,
           :city,
           :state,
           :zip_code,
           to: :customer,
           prefix: true
end

class Customer < ApplicationRecord
  has_one :address
  has_many :invoices

  delegate :street, :city, :state, :zip_code, to: :address
end

现在在我看来，我有以下代码

%tr
  = render partial: "row", locals: { data: invoice.id }
  = render partial: "row", locals: { data: invoice.customer_name }
  = render partial: "row", locals: { data: invoice.customer_street }
  = render partial: "row", locals: { data: invoice.customer_city }
  = render partial: "row", locals: { data: invoice.customer_state }
  = render partial: "row", locals: { data: invoice.customer_zip_code }

当我使用地址时，它正在执行 N+1 我在以下几行中包含客户

@invoices = Invoice.includes(:customer).all

但是我如何在其中添加地址，所以没有 N+1 查询地址出现。现在我已经修复了客户，只有两个查询来了，但我也需要在其中添加地址。

Answer 1

@invoices = Invoice.includes(customer: :address).all

每张发票包括客户，每张客户包括地址。