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Showing posts from April, 2013

Utility Dimensions in Tabular / PowerPivot

As my team having been porting a truck-load of hefty Excel reports over to PowerPivot, we've realized just how brilliant PowerPivot is in terms of fast turn-around time analytics. Unfortunately, Tabular doesn't have the maturity of a traditional OLAP engine - and one area where this is most evident is when working with time.

When source data presents fact records with multiple Date columns, a common trick used to avoid having multiple time dimensions is to implement a utility dimension, so that facts are filtered by a single date dimension - but the date column used for filtering is selected by the utility dimension.

PowerPivot/Tabular does not differentiate facts from dimensions, which creates something of a conundrum for report writers... how do you present an analytics model to end users without creating dozens of date dimensions?

In a nutshell, there are pretty much just 2 routes you can follow.... you either:

UNPIVOT your fact data when populating the tabular model, oruse …