September 2013
Intermediate to advanced
264 pages
5h
Chinese
Content preview from Bad Data 技術手冊
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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.
前後連貫（Coherent）
|
227
採取行動。我們到現在所討論的幾乎全部都是驗證：當你已經評估完整性之後，你應該
要採取什麼行動？在記錄層級的完整性的狀況中，這很簡單；要不就是你擁有全部的記
錄，要不就是沒有，而你接著要找到它們並且回填你的資料集合。但若你發現 10%（或
是任何對你有意義的門檻值）的記錄擁有遺失的值，而導致有些查詢無法被回答時，你
應該怎麼做？這些選擇通常會落在以下其中一個分類中：
• 修復遺失的資料。很好，若你能這麼做是最好的，但這並不總是可行或是實際的。
• 刪除導致問題的記錄。若你的查詢集合必須要互相一致時，這是個好選擇。
• 標記有問題的記錄，並且在查詢結果中附註它們的不完整性。
• 什麼都不做。依據你的查詢，你也許能夠直接執行分析，然而，在我的經驗中，這
通常不是個好的想法。
這邊只有四個選擇。一定還有更多選擇，但作出驗證以及後續行動之後，能夠節省相當
大的痛苦。
前後連貫（Coherent）
假設你的資料現在是完整的，或至少如你所需要的完整，下一步是什麼？你準備好要找
出隱藏在你的資料中的金礦了嗎？還沒這麼快—我們還有一些事情需要思考。在完整性
之後，下一個面向是
前後連貫
（
Coherent
）。簡單來說：
你的資料相對它本身來說是否
合理
？
更詳細的說明，你要確定這些互相相關的記錄是否是一致的，並且遵守資料集合的內部
邏輯。第一眼看起來，以資料分析的前提來說這是個有點多餘的概念；畢竟，關聯式資
料庫就是設計用來保證前後連貫的，如參考完整性（referential integrity ...
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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.