Chapter 9

Dimensional Modeling

Abstract

The purpose of dimensional modeling is to enable business intelligence (BI) reporting, query, and analysis. The key concepts in dimensional modeling are facts, dimensions, and attributes. There are different types of facts (additive, semiadditive, and nonadditive), depending on whether they can be added together. Dimensions can have different hierarchies, and have attributes that define the who, what, where, and why of the dimensional model. The grain, or level of granularity, is another key concept with dimensional modeling because it determines the level of detail. Facts, dimensions, and attributes can be organized in several ways (star, snowflake, multidimensional, and multifact star), called schemas. The ...

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