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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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.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.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.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.
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以下が関連エンティティです。
「支店」エンティティと「商品」エンティティは、多対多の関連を持っています。
一つの支店は複数の商品を扱いますし、一つの商品は複数の支店で売られている
からです。したがって、この二つのエンティティを直接ER図において関連させる
ことはできません。そこで両者の関連エンティティである「支店商品」を導入して、
多対多の関連を二つの1 対多の関連に分解しています。
たとえば以下のようなエンティティが考えられます。
❶消費者 - 商品
消費者は、一人が複数の商品を買うことができます。また、一つの商品は複数の
消費者に買われるので、多対多の関連になります。
これを解消するための関連実体は、「購入」または「注文」です。
❷学生 - 部活
学生は、一人が複数の部活をかけもちできます。また、一つの部活には複数の
学生が所属します。
これを解消するための関連実体は、「所属」です。
❸著者 - 書籍
著者は、一人が複数の書籍を書くことができます。書籍も、複数の著者（共著）
を持つことができます。
これを解消するための関連実体は、「著述」です。
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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.