August 2024
Intermediate to advanced
392 pages
10h 4m
Japanese
Content preview from 達人に学ぶDB設計徹底指南書 第2版
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に移し替えるような場合です。
それでは、データクレンジングとは、具体的にどのような処理を行なうのか、代
表的なものを紹介しましょう。この内容を理解すると、データクレンジングを怠っ
た場合にどのようなアンチパターンやグレーノウハウが生じるのかもわかるように
なります。
リレーショナルデータベースの考え方に慣れてくればくるほど、レコードを一意
に特定することのできる一意キー（ユニークキー）の存在は、当たり前のように思
えてきます。しかし、意外に世の中で行なわれている多くの業務では、データの一
意性については注意が払われていないことも多くあります。
たとえば、みなさんがホテルや旅館の利用者の帳簿をつける仕事をしていて、昔
ながらの紙で記録するやり方をしているとしましょう。この場合、日々の宿泊の記
録をとっているだけなら、宿泊客について一意なデータを作る必要は感じないかも
しれません。また、それをやろうとしても、宿泊客の中には、泊まるたびに「渡邊」
「渡辺」と新字と旧字で異なる表記をしたり、それどころか「ワタナベ」とカタカ
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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.