数据仓库(集市)之间共享维度表-Mysql Tutorial-php.cn

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数据仓库(集市)之间共享维度表

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Jun 07, 2016 pm 05:39 PM

storehouseshareddata

经常有朋友问到一个问题：事实表和维度表是不是一定要在一个数据库里面呢？为什么会有这样的问题呢？因为我们讲到，如果数据仓库足够大的话，可能会拆分为所谓的数据集市。而通常会按照所谓的业务模块的不同划分，例如人事管理的，销售管理，财务管理的等等

经常有朋友问到一个问题：事实表和维度表是不是一定要在一个数据库里面呢？

为什么会有这样的问题呢？因为我们讲到，如果数据仓库足够大的话，可能会拆分为所谓的数据集市。而通常会按照所谓的业务模块的不同划分，例如人事管理的，销售管理，财务管理的等等。

这样做看起来不错，美国空间，但随之而来又有一个问题了：这些数据库之间其实有点信息是共享的，例如员工信息。那么是不是每个数据集市中都要单独保存一份呢？

我想绝大部分情况下，如果每个数据集市都单独保存一份，这不是一个好的设计。一来数据是重复的，美国服务器，同时也带来了同步更新的问题。

那么，我们该如何跨数据库设计事实表和维度表的关系呢？事实上，只要你动手开始做，（而不仅仅是想），就会发现它并不是那么难

1. 下面的图，我展示了两个不同的数据。作为演示目的，我就是在HR数据库中建立了一个维度表DimEmployees，而在Sales数据库中建立了一个事实表FactSales。

很显然，我们不可能为他们在数据库内部设计好关系。但这又有什么问题呢？没有。数据仓库（或者数据集市）只是存数据，至于数据完整性的保证，我们还有其他很多方式（例如SSIS）来做。

2. 我们在设计Analysis Service项目的时候，需要添加两个数据源

3.同时，我们据此创建一个数据源视图

很多朋友都诧异地说，在这个对话框，我们显然是只能选择一个数据源的。是的，你没有看错。你在这个向导中，只需要选择任意一个数据源即可。我们要做的是，香港虚拟主机，先把这个数据源视图创建起来。

然后，就可以在数据源视图的空白处，点击右键，选择“添加/删除表…”

你会发现这里可以选择不同的数据源

4. 为这两个表创建关系，最终看到的效果如下

5. 创建Cube，设计维度，部署，处理，浏览

最后看到的效果如下

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