Rails使用 include 和 join 避免 N+1 query

May 10, 2015

Rails當中要連結model之間的關係非常簡單，不過也因為由於建立關係是這樣的簡便，造成許多指令會在讀取資料庫時有記憶體的浪費。例如我們建立以下關係：

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