DirectQuery vs Import mode in Power BI - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Difference in Data Refresh Frequency

Which statement correctly describes the data refresh behavior when using DirectQuery mode compared to Import mode in Power BI?

A Both DirectQuery and Import mode query the data source live on each interaction.

B DirectQuery mode queries the data source live on each interaction, while Import mode requires scheduled or manual refresh to update data.

C Both DirectQuery and Import mode require manual refresh to update data.

D Import mode queries the data source live on each interaction, while DirectQuery requires scheduled or manual refresh to update data.

💡 Hint

Think about how data is accessed in real-time versus stored locally.

DirectQuery mode sends queries directly to the data source every time you interact with the report, so data is always current. Import mode loads data into Power BI's memory and needs refreshes to update.

🎯 Scenario

intermediate

Choosing Mode for Large Dataset

You have a very large dataset that cannot fit into Power BI's memory. You want to build reports that always show the latest data without waiting for scheduled refreshes. Which mode should you choose?

A DirectQuery mode, because it queries the data source live and handles large datasets without loading all data into memory.

B Import mode, because it loads data into memory for faster queries.

C Neither mode can handle large datasets efficiently.

D Use Import mode with incremental refresh to handle large datasets.

💡 Hint

Consider how each mode handles data size and freshness.

DirectQuery mode is designed to work with large datasets by querying the source live, avoiding memory limits. Import mode loads data into memory, which can be problematic for very large datasets.

❓ dax_lod_result

advanced

DAX Query Behavior in DirectQuery Mode

Consider a Power BI report using DirectQuery mode connected to a SQL database. You create this DAX measure:

Sales Amount = SUM(Sales[Amount])

What happens when you interact with a slicer filtering by Product Category?

A Power BI caches all data on first load and does not query the database again.

B Power BI loads all Sales data into memory and applies the filter locally.

C Power BI ignores the slicer filter and returns total sales for all categories.

D Power BI sends a SQL query to the database with a WHERE clause filtering by the selected Product Category, returning only relevant data.

💡 Hint

Think about how DirectQuery mode handles filtering and queries.

In DirectQuery mode, Power BI translates DAX filters into SQL queries with WHERE clauses, so only filtered data is retrieved from the source.

🔧 Formula Fix

advanced

Performance Issue in DirectQuery Mode

A report using DirectQuery mode is very slow when filtering on a date column. Which of the following is the most likely cause?

A The report uses Import mode, which is slower than DirectQuery.

B Power BI caches too much data locally, causing memory overflow.

C The date column is not indexed in the source database, causing slow query performance.

D The data model has too many calculated columns in Power BI.

💡 Hint

Think about what affects query speed in the source database.

In DirectQuery mode, queries run on the source database. If columns used for filtering are not indexed, queries can be slow.

❓ visualization

expert

Visualizing Data Freshness Differences

You want to create a dashboard that clearly shows users the difference in data freshness between Import mode and DirectQuery mode. Which visualization approach best communicates this difference?

A Use a gauge visual showing last refresh time for Import mode and a live clock for DirectQuery mode.

B Use a pie chart showing percentage of data loaded in memory.

C Use a bar chart comparing total sales for both modes without timestamps.

D Use a table listing all data rows from both modes side by side.

💡 Hint

Think about how to show data freshness clearly and simply.

A gauge showing last refresh time for Import mode and a live clock for DirectQuery mode visually communicates how current the data is in each mode.

Practice

1. Which Power BI mode loads data into memory for faster report performance?

easy

A. Streaming mode

B. DirectQuery mode

C. Live Connection mode

D. Import mode

Solution

1. Step 1: Understand Import mode behavior

   Import mode loads data into Power BI's memory, enabling fast offline access.

2. Step 2: Compare with DirectQuery mode

   DirectQuery queries data live from the source, which can be slower due to network calls.

3. Final Answer:

   Import mode -> Option D

4. Quick Check:

   Import mode = loads data into memory [OK]

Hint: Import mode = data in memory for speed [OK]

Common Mistakes:

• Confusing DirectQuery as loading data into memory
• Thinking Live Connection is same as Import mode
• Assuming Streaming mode stores data in memory

2. Which of the following is the correct way to switch to DirectQuery mode when connecting to a SQL Server in Power BI?

easy

A. Choose 'DirectQuery' option during data source connection

B. Select 'Import' in the data source settings

C. Enable 'Live Connection' after loading data

D. Use 'Get Data' and then select 'Streaming dataset'

Solution

1. Step 1: Identify how to select connection mode

   When connecting to SQL Server, Power BI prompts to choose Import or DirectQuery mode.

2. Step 2: Confirm correct selection for DirectQuery

   Choosing 'DirectQuery' during connection enables live queries to the database.

3. Final Answer:

   Choose 'DirectQuery' option during data source connection -> Option A

4. Quick Check:

   DirectQuery selected at connection time [OK]

Hint: Pick DirectQuery option when connecting to data source [OK]

Common Mistakes:

• Selecting Import mode instead of DirectQuery
• Trying to enable DirectQuery after data load
• Confusing Live Connection with DirectQuery

3. Consider a Power BI report connected to a large sales database using DirectQuery mode. What is the expected behavior when a user filters the report by a specific product category?

medium

A. Power BI sends a live query to the database to fetch filtered data

B. The filter applies instantly using cached data in Power BI

C. The report crashes due to large data size

D. The filter does not work because DirectQuery does not support filtering

Solution

1. Step 1: Recall DirectQuery behavior on filtering

   DirectQuery mode sends queries live to the source database when filters change.

2. Step 2: Understand filtering effect

   Filtering triggers a new query to fetch only relevant data from the database.

3. Final Answer:

   Power BI sends a live query to the database to fetch filtered data -> Option A

4. Quick Check:

   DirectQuery filters trigger live queries [OK]

Hint: DirectQuery queries live on filter changes [OK]

Common Mistakes:

• Assuming filters use cached data in DirectQuery
• Believing DirectQuery disables filtering
• Thinking report crashes due to filtering

4. You created a Power BI report using Import mode but notice the data is outdated. What is the most likely cause and how to fix it?

medium

A. Data source is offline; switch to DirectQuery mode

B. Import mode does not support data refresh; use Live Connection

C. Data refresh is not scheduled; set up a refresh schedule

D. Report is corrupted; recreate the report

Solution

1. Step 1: Identify Import mode data update method

   Import mode loads data once and requires scheduled refresh to update data.

2. Step 2: Determine fix for outdated data

   Setting up a refresh schedule updates the imported data regularly.

3. Final Answer:

   Data refresh is not scheduled; set up a refresh schedule -> Option C

4. Quick Check:

   Import mode needs refresh schedule [OK]

Hint: Schedule refresh to update Import mode data [OK]

Common Mistakes:

• Thinking Import mode updates data automatically
• Confusing Import mode with DirectQuery refresh
• Assuming report corruption causes outdated data

5. A company has a very large dataset updated every minute and needs near real-time reports. Which Power BI mode should they choose and why?

hard

A. Import mode, because it provides the fastest report performance

B. DirectQuery mode, because it queries live data for up-to-date reports

C. Import mode, because it supports incremental refresh every minute

D. DirectQuery mode, because it caches data locally for faster access

Solution

1. Step 1: Analyze data size and update frequency

   Very large data updated every minute requires live querying to stay current.

2. Step 2: Match mode to requirements

   DirectQuery mode queries data live, providing near real-time updates without importing all data.

3. Final Answer:

   DirectQuery mode, because it queries live data for up-to-date reports -> Option B

4. Quick Check:

   Large, frequently updated data = DirectQuery [OK]

Hint: Use DirectQuery for large, frequently updated data [OK]

Common Mistakes:

• Choosing Import mode despite frequent updates
• Thinking incremental refresh updates every minute
• Believing DirectQuery caches data locally