November 2012
Beginner
528 pages
12h 9m
English
book
Knight's Microsoft SQL Server 2012 Integration Services 24-Hour Trainer
by Brian Knight, Devin Knight, Mike Davis, Wayne Snyder
Content preview from Knight's Microsoft SQL Server 2012 Integration Services 24-Hour Trainer
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Section 10
Loading a Warehouse
- Lesson 60: Dimension Load
- Lesson 61: Fact Table Load
Chapter 60
Dimension Load
If you have a data warehouse, you’ve probably been thumbing through this book looking for a way to load your dimension tables. Luckily, what used to take thousands of lines of code is now done with a simple wizard in SSIS. This Slowly Changing Dimension (SCD) Wizard is a Data Flow object that takes all the complexity out of creating a load process for your dimension table.
NOTE This lesson does not cover a Step-by-Step example on how to build a data warehouse from a design perspective because that is a book in itself.
Before we discuss the Slowly Changing Dimension Wizard, you must understand a bit of terminology. The wizard can handle three types of dimensions: Type 0, Type 1, and Type 2. Each of these types is defined on a column-by-column basis.
- A Type 0 (Fixed Attribute) dimension column does not allow you to make updates to it, such as a Social Security number. Even if the source value changes, the change is not propagated to a fixed attribute.
- A Type 1 (Changing Attribute) dimension handles updates, but does not track the history of such changes.
- A Type 2 (Historical Dimension) dimension tracks changes of a column. For example, if the price of a product changes and it’s a Type 2 column, the original row is expired, and a new row with the updated data is created.
The last term you need to be familiar with is inferred members (also called late arriving ...
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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.