August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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｜
405
在数据中使用标识符和键
图
46
-
1
：Purchases（采购）数据集，一个 Fact Tables（事实表）的例子
标识符也可以以布尔方式使用，表示某事是否为真。例如，
yes/
是（或
true/
真）通
常被编码为
1
，
no/
否或（
false/
假）为
0
。这种类型的逻辑通常没有相关的参考表，
但一些数据架构师为了清晰起见会坚持要有一个参考表。
46.2
什么是数据库中的
Key
（键）
键可以帮助我们确定如何将数据库中的表连接在一起。传统上，数据库术语中的键
有两种类型：
主键
一个在表中不能重复的唯一的标识符。
外键
存储在不同表中的、数据的唯一行的标识符。
图
46-2
展示了一个
Reference Tables
（参考表），该表对每个客户都有一个唯一的键。
图
46
-
2
：Customer（客户）数据集，一个参考表的例子
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