MDFT Pro, a well-known training agency, is building a Power BI model to analyze student enrollment and course sales. You plan to create the model shown in the exhibit.
The data has the following refresh requirements:
- Customer must be refreshed daily.
- Date must be refreshed once every three years.
- Sales must be refreshed in near real time.
- SalesAggregate must be refreshed once per week.
You need to select the storage modes for the tables. The solution must meet the following requirements:
- Minimize the load times of visuals.
- Ensure that the data is loaded to the model based on the refresh requirements.
Which storage mode should you select for each table?
Dual is incorrect. Dual mode caches data, which would not provide the near real-time freshness required by the Sales table.
DirectQuery is correct. DirectQuery queries the source directly on every interaction, providing the near real-time data freshness required by the Sales table.
Import is incorrect. Import mode caches data and requires scheduled refreshes, so it cannot provide the near real-time freshness required by the Sales table.
DirectQuery is incorrect. DirectQuery would query the source on every interaction, slowing visual load times for SalesAggregate which only needs weekly refresh and does not require near real-time data.
Dual is incorrect. Dual mode adds unnecessary query overhead for SalesAggregate, which only requires a weekly refresh and does not need DirectQuery compatibility.
Import is correct. Import mode caches data for fast visual loading and only requires weekly refreshes, making it the optimal choice for SalesAggregate.
Import is incorrect. Import mode would create a limited relationship with the DirectQuery Sales table, increasing visual load times when filtering across tables.
DirectQuery is incorrect. DirectQuery does not cache the Date table, so it would query the source on every interaction and slow visual load times. Date only needs refreshing every three years, so Import or Dual with caching is more appropriate.
Dual is correct. Dual mode caches data for fast visual loading while also supporting DirectQuery relationships. Date is a small dimension table that is queried frequently across all tables including DirectQuery Sales, so Dual ensures fast cross-filtering without slowing visuals.
Import is incorrect. Import mode would create a limited relationship with the DirectQuery Sales table, increasing visual load times when filtering across tables.
Dual is correct. Dual mode caches data for fast visual loading while also supporting DirectQuery relationships, meeting the daily refresh requirement for Customer and ensuring compatibility with DirectQuery tables like Sales.
DirectQuery is incorrect. DirectQuery does not cache data, so it would not meet the daily refresh requirement for the Customer table and would slow visual load times by querying the source on every interaction.