From the course: Implementing a Data Warehouse with Microsoft SQL Server 2012
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Working with slowly changing dimensions - SQL Server Tutorial
From the course: Implementing a Data Warehouse with Microsoft SQL Server 2012
Working with slowly changing dimensions
I'd like to talk about slowly changing dimensions. This is a topic we introduced in the previous section where we talked about loading modified data. We talked about three main types of slowly changing dimensions. A type one, where we overwrite the old data. Type two, where we add a row to the same table with the new data. And type three, where we add columns to the same table to store modified data. These three types are certainly the most commonly used in the industry. They are very well defined, and pretty much everyone agrees on what is a type one, a type two, and a type three. You will occasionally hear about other types. Everything from type zero to type seven. Some of these do not have standard definitions, with different vendors defining and implementing a type five slightly differently. I'm going to work through some of these briefly, and I'll try to give you the most common definition of each one. With the type zero slowly changing dimensions, you don't change anything. When…
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