Rails嵌套N + 1查詢問題

Question

我的協會是這樣的：

vendor has shipments  
shipment has order
order has products

在我的控制器中，我寫了

@shipments = @vendor.shipments.includes(:order)

但在我看來，我正在使用

shipment.order.products.collect(&:name)

所以它正在返回Rails'bullet'gem的N + 1 Query問題

任何人幫我解決嵌套N + 1查詢問題？ 我怎么需要在控制器中寫？

Answer 1

@shipments = @vendor.shipments.includes(:order => :products)

應該管用。 在這里閱讀更多相關信息http://guides.rubyonrails.org/active_record_querying.html#nested-associations-hash