Question

我的模型设置方式：

Order对象有很多RentalItems＆amp; TypeLogistics
RentalItem＆amp; TypeLogistic对象每个都有许多ChargedAmounts＆amp;退款
此外，Order对象本身有许多ChargedAmounts＆amp;退款

以下查询似乎正常工作，因为我想在db中急切加载第19个Order对象的声明关联：

# Load order, and its charged_amounts & refunds
@order = Order.includes(:charged_amounts, :refunds).find(19)
=>
Order Load (0.2ms)  SELECT  "orders".* FROM "orders"  WHERE "orders"."id" = ? LIMIT 1  [["id", 19]]
ChargedAmount Load (0.3ms)  SELECT "charged_amounts".* FROM "charged_amounts"  WHERE "charged_amounts"."order_id" IN (19)
Refund Load (0.3ms)  SELECT "refunds".* FROM "refunds"  WHERE "refunds"."order_id" IN (19)

# Load order, its type_logistics, and the charged_amounts & refunds that belong to each type_logistic
@order = Order.includes(type_logistics:[:charged_amounts, :refunds]).find(19)
=>
Order Load (0.1ms)  SELECT  "orders".* FROM "orders"  WHERE "orders"."id" = ? LIMIT 1  [["id", 19]]
TypeLogistic Load (1.1ms)  SELECT "type_logistics".* FROM "type_logistics"  WHERE "type_logistics"."order_id" IN (19)
ChargedAmount Load (0.3ms)  SELECT "charged_amounts".* FROM "charged_amounts"  WHERE "charged_amounts"."type_logistic_id" IN (26)
Refund Load (0.2ms)  SELECT "refunds".* FROM "refunds"  WHERE "refunds"."type_logistic_id" IN (26)

# Load order, its rental_items, and the charged_amounts & refunds that belong to each rental_item
@order = Order.includes(rental_items: [:charged_amounts, :refunds]).find(19)
=>
Order Load (0.3ms)  SELECT  "orders".* FROM "orders"  WHERE "orders"."id" = ? LIMIT 1  [["id", 19]]
RentalItem Load (0.2ms)  SELECT "rental_items".* FROM "rental_items"  WHERE "rental_items"."order_id" IN (19)
ChargedAmount Load (0.2ms)  SELECT "charged_amounts".* FROM "charged_amounts"  WHERE "charged_amounts"."rental_item_id" IN (27, 28)
Refund Load (0.1ms)  SELECT "refunds".* FROM "refunds"  WHERE "refunds"."rental_item_id" IN (27, 28)

但挑战在于我想急切加载所有这些：订单的charge_amounts和退款，以及所有的rental_items和type_logistics以及每个rental_item和type_logistic的charge_amounts和退款。

但是当我将查询串在一起时，看起来第二组关联（type_logistics及其charge_amounts和refunds）根本不会根据查询加载。

@order = Order.includes(:charged_amounts, :refunds, rental_items: [:charged_amounts, :refunds], type_logistics:[:charged_amounts, :refunds]).find(19)
=>
Order Load (0.2ms)  SELECT  "orders".* FROM "orders"  WHERE "orders"."id" = ? LIMIT 1  [["id", 19]]
ChargedAmount Load (0.2ms)  SELECT "charged_amounts".* FROM "charged_amounts"  WHERE "charged_amounts"."order_id" IN (19)
Refund Load (0.2ms)  SELECT "refunds".* FROM "refunds"  WHERE "refunds"."order_id" IN (19)
RentalItem Load (0.2ms)  SELECT "rental_items".* FROM "rental_items"  WHERE "rental_items"."order_id" IN (19)
ChargedAmount Load (0.1ms)  SELECT "charged_amounts".* FROM "charged_amounts"  WHERE "charged_amounts"."rental_item_id" IN (27, 28)
Refund Load (0.1ms)  SELECT "refunds".* FROM "refunds"  WHERE "refunds"."rental_item_id" IN (27, 28)

但订单上的charge_amounts和退款没有任何其他关联，所以它们不是任何东西的“关键”。有什么帮助吗？

Answer 1

我在之前的项目中遵循的方法是：

Order.eager_load(:charged_amounts, :refunds)
      .eager_load(rental_items: [:charged_amounts, :refunds])
      .eager_load(type_logistics: [:charged_amounts, :refunds] )
      .find(19)

我不知道这可能是解决方案。另请注意，我使用的是AR.eager_load方法。随意交换AR.includes

Rails ActiveRecord包含多个父/子

1 个答案: