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This is my last notes on dimension modeling.
Avoid unnecessary normalizing. In a star schema, the practice of normalizing is called snowflaking. This is usually unnecessary, unless your dimension tables is so large it needs to be physically separated on the storage array.
CamelCasing, the capita......
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Here is my notes #11. About dimension again.
It’s easier to demonstrate the Type 0, Type 1 and Type 2 and Type 3 SCD (Slowly Changing Dimension) using the SCD Wizard in SSIS.
Type 0: any change in the dimension column is treated as errors.
Type 1: Update changing data only, no historical ......
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Here is my notes #10.
On a very high level, dimensions provides the means to "slice and dice" data in a data warehouse. The primary function of dimensions is threefold: to provide filtering, grouping and labeling. It answers the where-clause questions for us. Look for word “by” in busin......
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I guess my notes about dimension modeling will not be very complete if I do not show a typical snowflake schema.
In this typical snowflake schema example, the dimension Product is normalized, because the Product Sub Category is stored in a separate table ProductSubCategory. ProductSubCategory is al......
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Here is an article from www.SearchSQLServer.com:
http://viewer.media.bitpipe.com/1216309501_94/1268760175_892/Master-Data-Management-Projects-in-Practice_An-Information-Difference-Research-Study.pdf......
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Here is what Wikipedia (http://en.wikipedia.org/wiki/Master_Data_Management) defines Master Data Management:
In computing, master data management (MDM) comprises a set of processes and tools that consistently defines and manages the non-transactional data entities of an organization (which may incl......
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Read this article:
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What Is Master Data?
Most software systems have lists of data that are shared and used by several of the applications that make up the system. For example, a typical ERP system as a minimum will have a Customer Master, an Item Master, and an Account Master. This master data is often one of the key ......
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The employee hierarchy table is just one physical table, with a date range to keep employee’s employment history. This same employee hierarchy table can be used sometimes to show different business functional teams, for example, LAS VS. Underwriters on the same fact table.
I can simply creat......
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Chapter 4 “Cleaning and Conforming” from Kimball’s The Data Warehouse ETL Toolkit takes about 50 pages, not an extremely long chapter. Here is a warning from the beginning of the chapter.
Please stay with us in this chapter. It is enormously important. This chapter
makes a serio......
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