8 Core Principles of Data Warehouse Design – #2 Dimensional Model

The reasons for building a data warehouse are different forms of reporting and analytics, activities that require slicing and dicing of data in an accessible and comprehensible form. A dimensional model is a great way to provide this clear view of the data. I’m not going to show how to create the dimensional model in this series, but I do want to make the point that a good data warehouse includes a dimensional model.

Begin the modeling process by turning business requirements into a conceptual star schema. Draw simple diagrams with facts in the middle of the star and dimensions surrounding it. Give the facts and dimensions high-level names, such as Measurements and Factory. Continue through the requirements and conceptual modeling process until you’ve completely identified all the facts and dimensions. Then create a logical model by defining the columns that will make up each fact and dimension, and identify each column as a string or a number. This logical model should be able to answer all of the questions posed by the business requirements, and it can then be turned into your physical data warehouse.
Providing a good dimensional model will make your business users and your IT staff who have to use the data warehouse very happy. It is a much easier way for them to get the data they need from the data warehouse.
For more info on dimensional modeling, start with the Kimball books and web site. Go to http:\\www.ralphkimball.com.

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