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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180
定期的に現在のデータを
記録しておく
6-6
データベースは常にデータ破損の危険と隣り合わせです。例えば操作す
るロジックのバグでデータに矛盾が生じたり、操作ミスでデータが消えて
しまうことがあります。また、物理的に機器が壊れてしまうと中のデータ
が復旧できなくなってしまいます。このような場合に備えてデータを複製
しておくことをバックアップといい、もしデータが破損してしまっても、
ができます（図6-10）。
バックアップは以下のような方式があります（図6-11）。
フルバックアップ
方法で、その時点のデータを
後から完全に復旧することができます。ただし大量のデータを取得す
るため処理に時間がかかることや、システムに負荷がかかるため、バ
ックアップの頻度が多いケースには不向きです。
差分バックアップ
フルバックアップ後に方法で
す。データ復旧の際は、最初のフルバックアップと最新の差分バック
アップの2 つのファイルを使って復旧します。変更分だけのバックア
ップなので、処理の時間が短く、システムへの負担が少なくすみます。
増分バックアップ
フルバックアップ後の変更分をバックアップする方法で差分バック
アップと似ていますが、
やり方です。よりシステムに負担 ...
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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.
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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.