Wednesday, September 23, 2015

Different types of Dimensions

There are three types of dimensions are available in dimensional approach.
Conformed dimension: It is a set of data attributes which is physically implemented in multiple database tables using same structure, attributes, domain values, definitions and concepts in each implementation. It cuts across many facts.
Dimensions are conformed when they are either same(with keys) or one is perfect subset of other.

Junk Dimension: It is grouping of low cardinality flags and indicators. These flags and indicators are removed from the fact table while placing them into a useful dimensional framework.

Role Playing Dimension: Often dimensions are recycled for multiple applications within the same database. i.e. “date” dimension can be used for “sales date” or “hire date”. This is referred as role playing dimension

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