Microsoft Certified: Fabric Analytics Engineer AssociateImplement and manage semantic models (30-35%)Medium
A data engineer is designing a semantic model in Microsoft Fabric. The model will contain a 'Product' dimension table that is relatively small and frequently queried. The 'Sales' fact table is very large. The engineer wants to ensure that queries involving the 'Product' dimension are always fast, while still allowing the 'Sales' fact table to be queried directly from the source for the latest data without importing it. Which storage mode should be applied to the 'Product' dimension table?
- ALive Connection mode
- BDual mode
- CDirectQuery mode
- DImport mode
Show answer & explanationAnswer & explanation
Correct answer: B. Dual mode
Dual mode allows a table to behave as both Import and DirectQuery depending on the query context. For a small, frequently queried dimension table, it can be cached (Import) for speed, while still participating in DirectQuery queries against larger fact tables without data duplication.
Why the other options are wrong
- A. Live Connection is for connecting to an existing dataset, not for setting storage mode of individual tables within a new model.
- C. DirectQuery mode for 'Product' would mean slower queries against this small, frequently accessed table, which is inefficient.
- D. Import mode for 'Product' is good for speed, but if 'Sales' is DirectQuery, it would force the entire query to DirectQuery if not handled by Dual mode.
Dual Storage Mode
A table storage mode in Power BI/Fabric that allows a table to act as both Import and DirectQuery, chosen by the query engine based on the query's needs for optimal performance.
- Optimizes performance in mixed-mode models.
- Typically used for dimension tables.
- Reduces the number of DirectQuery queries to data sources.
Memory trick: Dual for dimensions, Import for facts, Direct for real-time.