Refining Cube Dimensions
Once a cube has been created, dimensions should be refined by updating attributes and hierarchies.
With respect to hierarchies, there are two primary types – natural and reporting.
Natural hierarchies contains relationships between levels and expand as they are traversed.
One example of a natural hierarchy resides within the Geography dimension. Upon inspection of this dimension’s attributes, you will see the Postal Code attribute when then naturally relates to the City attributes, which then relates to State, and so on.
The next type of hierarchy is one where dimension attributes contain no natural relationships, but are necessary for reporting purposes.
The customer dimension below illustrates a reporting type of hierarchy with is Postal Code and Commute Distance attributes – neither attribute naturally relates to a customer as part of its natural attributes, but is necessary for reporting.