August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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419
第
48
章
使用历史表
实时数据连接是一种奇妙的方式，可以让你的数据分析保持相关性，并防止每次更
新数据集时重复工作，这种情况可能是频繁的。构建连接到实时数据集的数据可视
化，可以让最终用户相信他们正在获得关于主题的最新视图。
频繁更新数据的问题在于，需要决定如何处理那些在不再关联更新的或已经删除了
的记录。构建历史表可以让你在设定的时间间隔内记录数据点，而不用担心它们会
被覆盖并永远丢失。
48.1
为什么需要历史表
在分析数据时，用户会提出很多问题，以全面了解数据集中的关键趋势、异常值和
意外结果。然而，一旦找到这些数据点，用户就会想知道：
•
为什么这些趋势或数据点会有这样的表现？
•
一直以来都是这样的吗？
第一个问题与数据收集背景有关，它可能很难回答。通常情况下，与业务专家合作
会有帮助。第二个问题往往归结为是否有历史数据可以借鉴。尽管数据的存储成本
不断降低，但是数据集的快速增长会使保留足够的历史数据点来回答这个问题变得
很有挑战性。
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