The detail table is named FactSales and the aggregation table is named FactSales(Agg). You need to aggregate SalesAmount for each store. Which type of summarization should you use for SalesAmount…

Question

Explanation

This question tests your ability to configure aggregation tables in Power BI Desktop by selecting the correct summarization type for each column when mapping a detail table (FactSales) to an aggregation table (FactSales(Agg)).

Approach. For SalesAmount, you should use Sum summarization - it is a numeric additive measure, and the aggregation table pre-computes the summed value per store so Power BI can redirect queries to the faster aggregate table instead of scanning the detail table. For StoreKey, you should use GroupBy summarization - it is the dimension key used to define the granularity of the aggregation (one row per store), so it acts as the grouping column rather than a value being aggregated. Together, Sum on SalesAmount and GroupBy on StoreKey tells Power BI: 'when a query filters or groups by StoreKey and sums SalesAmount, hit FactSales(Agg) instead of FactSales.'

Concept tested. Power BI aggregation table configuration - specifically assigning correct summarization types (Sum vs. GroupBy) in the 'Manage Aggregations' dialog to enable query redirection from a large detail fact table to a smaller pre-aggregated table for performance optimization.

Reference. Microsoft Docs: 'Use aggregations in Power BI Desktop' - manage-aggregations section describing Summarization options (Sum, Min, Max, Count, GroupBy)

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