PL-300 Question #479: Real Exam Question with Answer & Explanation

Question

You have a Power BI semantic model that contains the following tables. You need to define a relationship from FactSales to DimProduct. The solution must ensure the fastest DAX query performance. Which cardinality should you use?

Options

• Aone-to-many
• Bone-to-one
• Cmany-to-many
• Dmany-to-one

Explanation

In a standard star schema, a fact table contains many rows referencing each dimension record. From the perspective of FactSales, there are many sales rows per product, but each product key in DimProduct is unique - making the relationship many (FactSales) to one (DimProduct). When defining the relationship from FactSales to DimProduct, the correct cardinality is many-to-one (D). This is the optimal cardinality for fact-to-dimension relationships: the VertiPaq engine handles it most efficiently, enabling faster DAX query performance than many-to-many (C), which requires additional bridge logic and is slower. One-to-many (A) describes the direction from DimProduct to FactSales. One-to-one (B) would imply each fact row maps to exactly one unique dimension row with no duplicates on either side, which does not model a fact-dimension relationship correctly.

No community discussion yet for this question.