January 2021
Intermediate
240 pages
5h 32m
Japanese
Content preview from 図解まるわかり データベースのしくみ
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158
テーブルやカラムの名前を決める
5-15
テーブルやカラムの名前は英数字を使うのが主流です。日本語で作成す
ると環境によっては動作しなかったり、不用意なエラーが発生することも
考えられますので、です。
他にもテーブル名やカラム名をつけるときの命名規則や、わかりやすい名
前を付けるコツを以下にまとめました。これが正解というものではないの
で、必要に応じて参考にしてみてください（図5-26）。
テーブル名やカラム名には半角英数字とアンダーバーのみを使う
大文字を使わず、すべて小文字に統一し、最初の文字に数字は使わない
テーブル名は複数形にする
他の人が見てわかりやすい名前にする（略語を避けるなど）
他のテーブルの主キーとjoinするためのカラムは「テーブル名（単数
系）̲id」に統一する（user̲id,item̲idなど）
カラムになんの種類の値が保存されているかわかるようにする
（BOOLEAN 型の場合は「is̲◯◯◯」、日時の場合は「◯◯◯ ̲at」など）
カラム名に「◯◯◯ ̲flag」は避ける（例えば「delete̲flag」ではなく
「is̲deleted」とすると、trueのときが削除された状態だとわかる）
は別の名前なのに同じ意味を持つ言葉のことで、例えば商品を
示す言葉として「item」や「product」がありますが、どちらかに統一し
ましょう。同じ種類のデータだとわかるので混乱せずにすみます。 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.