Rails基礎固め24のTips Advent Calendar 2025

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Category：Solo Advent Calendar

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@gon0821

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Railsの基礎的な部分に関してまとめていきたいと思います！
初学者の人が読んだ時に勉強になるような内容になるように分かりやすく書いていきます📚

How to join the calendar

You can join the calendar by selecting an available date and registering the URL of the article you wish to link to. If a slot is available, you can go back to a past date to join!

Series 1

Sunday	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday
30	@gon0821 【Rails初学者】enumの基礎についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】ActiveRecordの基礎についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】マイグレーションの基礎についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part1（概要編） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part2（各種バリデータの詳細） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part3（各種バリデータの詳細） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use
@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part4（共通オプション） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part5（カスタムバリデーション） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part6（errors/エラー対応） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【初PR】Railsガイドの表記誤りを見つけたので、修正PRを送ってマージ🙆された話 Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】ActionViewの概要についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】ActionViewのパーシャルについてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】パーシャルにはインスタンス変数ではなくローカル変数を渡せ🫡 Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use
@gon0821 【Rails初学者】「render」と「redirect_to」の使い分けをざっくり理解する🤔 Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】Railsでメールが送信できる仕組みをざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】「Date.today」と「Date.current」の違いを理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part1 \| 20年の軌跡（2003年〜2006年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part2 \| 20年の軌跡（2007年〜2009年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part3 \| 20年の軌跡（2010年〜2012年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part4 \| 20年の軌跡（2013年〜2015年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use
@gon0821 【Rails史】Railsの過去を知る -Part5 \| 20年の軌跡（2016年〜2018年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part6 \| 20年の軌跡（2019年〜2021年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part7 \| 20年の軌跡（2022年〜2024年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る \| 20年の軌跡📚（総集編） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【初参加】アドベントカレンダー2025を通して思ったこと Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	26	27

@gon0821
【Rails初学者】enumの基礎についてざっくり理解する
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Title
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About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
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Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
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@gon0821
【Rails初学者】ActiveRecordの基礎についてざっくり理解する
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If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
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Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
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@gon0821
【Rails初学者】マイグレーションの基礎についてざっくり理解する
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Title
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You can post either your article on Qiita or your blog post.
About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
About posting period
Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part1（概要編）
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part2（各種バリデータの詳細）
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Title
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part3（各種バリデータの詳細）
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You can post either your article on Qiita or your blog post.
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About posting period
Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part4（共通オプション）
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If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part5（カスタムバリデーション）
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You can post either your article on Qiita or your blog post.
About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
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Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part6（errors/エラー対応）
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When you participate, we will assume that you have agreed to the terms of use
@gon0821
【初PR】Railsガイドの表記誤りを見つけたので、修正PRを送ってマージ🙆された話
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You can post either your article on Qiita or your blog post.
About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
About posting period
Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】ActionViewの概要についてざっくり理解する
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You can post either your article on Qiita or your blog post.
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If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
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Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】ActionViewのパーシャルについてざっくり理解する
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Title
URL
You can post either your article on Qiita or your blog post.
About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
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Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】パーシャルにはインスタンス変数ではなくローカル変数を渡せ🫡
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Title
URL
You can post either your article on Qiita or your blog post.
About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
About posting period
Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】「render」と「redirect_to」の使い分けをざっくり理解する🤔
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Title
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You can post either your article on Qiita or your blog post.
About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
About posting period
Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】Railsでメールが送信できる仕組みをざっくり理解する
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About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
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Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails初学者】「Date.today」と「Date.current」の違いを理解する
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Title
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You can post either your article on Qiita or your blog post.
About reserved posting
If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
About posting period
Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails史】Railsの過去を知る -Part1 | 20年の軌跡（2003年〜2006年）
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When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails史】Railsの過去を知る -Part2 | 20年の軌跡（2007年〜2009年）
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You can post either your article on Qiita or your blog post.
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If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day.
About posting period
Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.)
When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails史】Railsの過去を知る -Part3 | 20年の軌跡（2010年〜2012年）
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When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails史】Railsの過去を知る -Part4 | 20年の軌跡（2013年〜2015年）
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When you participate, we will assume that you have agreed to the terms of use
@gon0821
【Rails史】Railsの過去を知る -Part5 | 20年の軌跡（2016年〜2018年）
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@gon0821
【Rails史】Railsの過去を知る -Part6 | 20年の軌跡（2019年〜2021年）
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【Rails史】Railsの過去を知る -Part7 | 20年の軌跡（2022年〜2024年）
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@gon0821
【Rails史】Railsの過去を知る | 20年の軌跡📚（総集編）
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@gon0821
【初参加】アドベントカレンダー2025を通して思ったこと
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Sunday	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday
30	@gon0821 【Rails初学者】enumの基礎についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】ActiveRecordの基礎についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】マイグレーションの基礎についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part1（概要編） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part2（各種バリデータの詳細） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part3（各種バリデータの詳細） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use
@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part4（共通オプション） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part5（カスタムバリデーション） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】バリデーションの基礎についてざっくり理解する -Part6（errors/エラー対応） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【初PR】Railsガイドの表記誤りを見つけたので、修正PRを送ってマージ🙆された話 Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】ActionViewの概要についてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】ActionViewのパーシャルについてざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】パーシャルにはインスタンス変数ではなくローカル変数を渡せ🫡 Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use
@gon0821 【Rails初学者】「render」と「redirect_to」の使い分けをざっくり理解する🤔 Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】Railsでメールが送信できる仕組みをざっくり理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails初学者】「Date.today」と「Date.current」の違いを理解する Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part1 \| 20年の軌跡（2003年〜2006年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part2 \| 20年の軌跡（2007年〜2009年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part3 \| 20年の軌跡（2010年〜2012年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part4 \| 20年の軌跡（2013年〜2015年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use
@gon0821 【Rails史】Railsの過去を知る -Part5 \| 20年の軌跡（2016年〜2018年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part6 \| 20年の軌跡（2019年〜2021年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る -Part7 \| 20年の軌跡（2022年〜2024年） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【Rails史】Railsの過去を知る \| 20年の軌跡📚（総集編） Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	@gon0821 【初参加】アドベントカレンダー2025を通して思ったこと Overwrite Title URL You can post either your article on Qiita or your blog post. About reserved posting If you register a secret article by the day before the same day, it will be automatically published around 7:00 on the same day. About posting period Only articles submitted after October 31, 2025 can be registered. (Secret articles can be registered anytime articles are posted.) When you participate, we will assume that you have agreed to the terms of use	26	27

@gon0821
【Rails初学者】enumの基礎についてざっくり理解する
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@gon0821
【Rails初学者】ActiveRecordの基礎についてざっくり理解する
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@gon0821
【Rails初学者】マイグレーションの基礎についてざっくり理解する
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part1（概要編）
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【Rails初学者】バリデーションの基礎についてざっくり理解する -Part2（各種バリデータの詳細）
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part3（各種バリデータの詳細）
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part4（共通オプション）
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part5（カスタムバリデーション）
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@gon0821
【Rails初学者】バリデーションの基礎についてざっくり理解する -Part6（errors/エラー対応）
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@gon0821
【初PR】Railsガイドの表記誤りを見つけたので、修正PRを送ってマージ🙆された話
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@gon0821
【Rails初学者】ActionViewの概要についてざっくり理解する
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@gon0821
【Rails初学者】ActionViewのパーシャルについてざっくり理解する
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@gon0821
【Rails初学者】パーシャルにはインスタンス変数ではなくローカル変数を渡せ🫡
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@gon0821
【Rails初学者】「render」と「redirect_to」の使い分けをざっくり理解する🤔
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@gon0821
【Rails初学者】Railsでメールが送信できる仕組みをざっくり理解する
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@gon0821
【Rails初学者】「Date.today」と「Date.current」の違いを理解する
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@gon0821
【Rails史】Railsの過去を知る -Part1 | 20年の軌跡（2003年〜2006年）
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【Rails史】Railsの過去を知る -Part2 | 20年の軌跡（2007年〜2009年）
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【Rails史】Railsの過去を知る -Part3 | 20年の軌跡（2010年〜2012年）
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【Rails史】Railsの過去を知る -Part4 | 20年の軌跡（2013年〜2015年）
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【Rails史】Railsの過去を知る -Part5 | 20年の軌跡（2016年〜2018年）
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【Rails史】Railsの過去を知る -Part6 | 20年の軌跡（2019年〜2021年）
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【Rails史】Railsの過去を知る -Part7 | 20年の軌跡（2022年〜2024年）
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【Rails史】Railsの過去を知る | 20年の軌跡📚（総集編）
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【初参加】アドベントカレンダー2025を通して思ったこと
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You can increase the number of series when Calendar 1 is filled with more than 10 articles.

Rails基礎固め24のTips Advent Calendar 2025

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