Thursday, July 17, 2014

How many types of dimensions?

They are 4 types of dimensions:

  • Conformed dimension
  • Junk dimension
  • Degenerate attribute
  • Role-playing dimension   

Conformed dimension:
It is the dimension which is sharable across the multiple facts or data model. This is also called as Role Playing Dimensions.
Junk dimension:
A number of very small dimensions might be lumped (a small irregularly shaped) together to form a single dimension, a junk dimension – the attributes are not closely related. Grouping of Random flags and text attributes in a dimension and moving them to a separate sub dimension is known as junk dimension.
Degenerated dimension:
In this degenerate dimension contains their values in fact table and the dimension id not available in dimension table. Degenerated Dimension is a dimension key without corresponding dimension.
Role-playing dimension:

Dimensions which are often used for multiple purposes within the same database are called role-playing dimensions. For example, a date dimension can be used for “date of sale", as well as "date of delivery", or "date of hire".

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