SQL Server 2019 Analysis Services CTP 2.301-04-2019 0 Comment(s)
Here is a question for seasoned BI professionals: what is the most powerful feature of SSAS multidimensional? Many would say the ability to define calculated members, typically using scoped cell assignments. Calculated members in multidimensional enable complex calculations by reusing calculation logic. Unfortunately, Analysis Services tabular doesn’t have equivalent functionality. Correction: it does now!!!
Calculation groups address the issue of proliferation of measures in complex BI models often caused by common calculations like time-intelligence. Enterprise models are reused throughout large organizations, so they grow in scale and complexity. It is not uncommon for Analysis Services models to have hundreds of base measures. Each base measure often requires the same time-intelligence analysis. For example, Sales and Order Count may require:
- Sales MTD, Sales QTD, Sales YTD, Sales PY, Sales YOY%, …
- Orders MTD, Orders QTD, Orders YTD, Orders PY, Orders YOY%, …
As you can see, this can easily explode the number of measures. If a model has 100 base measures and each requires 10 time-intelligence representations, the model ends up with 1,000 measures in total (100*10). This creates the following problems.
- The user experience is overwhelming because must sift through so many measures
- DAX is difficult to maintain
- Model metadata is bloated
Calculation groups address these issues. They are presented to end-users as a table with a single column. Each value in the column represents a reusable calculation that can be applied to any of the measures where it makes sense. The reusable calculations are called calculation items.
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