1:N な関係でN個の中で最新のレコードだけ欲しい、っていうケースで has_manyなrelationのfirstを取得していくとN+1になりまくってつらいので has_oneで取得できるようにしてeager_loadする方法を調査したメモ 環境 OS: Ubuntu 20.04 Ruby: 3.0.2 Rails: 6.1.4.1 RDB: Postgres 13 薄いプロジェクトを作る FROM ruby:3.0.2-alpine3.12 as ruby ## Development FROM ruby AS dev ENV BUNDLE_FORCE_RUBY_PLATFORM=1 \ CFLAGS="-Wno-cast-function-type" RUN apk update \ && apk add --no-cache \ gcc \ g++ \ libc-dev \ lin
![[Rails] has_oneで最新のレコードを取得できるようにしてeager_loadしたい](https://cdn-ak-scissors.b.st-hatena.com/image/square/490a4820e6c0faad8162df2733a0d7fc773fd9dc/height=288;version=1;width=512/https%3A%2F%2Fres.cloudinary.com%2Fzenn%2Fimage%2Fupload%2Fs--SHTYOo35--%2Fc_fit%252Cg_north_west%252Cl_text%3Anotosansjp-medium.otf_55%3A%25255BRails%25255D%252520has_one%2525E3%252581%2525A7%2525E6%25259C%252580%2525E6%252596%2525B0%2525E3%252581%2525AE%2525E3%252583%2525AC%2525E3%252582%2525B3%2525E3%252583%2525BC%2525E3%252583%252589%2525E3%252582%252592%2525E5%25258F%252596%2525E5%2525BE%252597%2525E3%252581%2525A7%2525E3%252581%25258D%2525E3%252582%25258B%2525E3%252582%252588%2525E3%252581%252586%2525E3%252581%2525AB%2525E3%252581%252597%2525E3%252581%2525A6eager_load%2525E3%252581%252597%2525E3%252581%25259F%2525E3%252581%252584%252Cw_1010%252Cx_90%252Cy_100%2Fg_south_west%252Cl_text%3Anotosansjp-medium.otf_37%3Ayagince%252Cx_203%252Cy_121%2Fg_south_west%252Ch_90%252Cl_fetch%3AaHR0cHM6Ly9saDMuZ29vZ2xldXNlcmNvbnRlbnQuY29tL2EtL0FPaDE0R2dlSHBvV3FEWmVSamhpUnlUQm4wMnk0MkxwMUdCa0pNMEtHdW5SMnc9czI1MC1j%252Cr_max%252Cw_90%252Cx_87%252Cy_95%2Fv1627283836%2Fdefault%2Fog-base-w1200-v2.png)