PL-300 Practice Test 13 — 15 Questions

Question 1

You are reviewing a Power Query query that loads data from a SQL Server database. The query includes multiple steps that perform data transformation. You want to ensure that the query is optimized by pushing as many transformations as possible to the SQL Server. What should you look for?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Check for the 'Query Folding' indicators in the query editor.. Query folding indicators in Power Query Editor show whether transformations are being pushed to the SQL Server source. When a step shows a 'folded' icon (a table with a down arrow), it means the transformation is translated into native SQL and executed on the server, reducing data transfer and improving performance. Checking these indicators directly confirms which steps are folded and which are not, allowing you to optimize the query by reordering or rewriting steps to maximize folding.

Option A is incorrect because viewing the native SQL query only shows the final aggregated SQL, not the folding status of each individual step. Option B is also incorrect as the Performance Analyzer helps measure overall report performance but does not indicate folding for each step. Option D is irrelevant because data previews do not show folding status.

Answer

View the native SQL query generated by Power Query.

Answer

Use the Performance Analyzer in Power BI Desktop.

Answer

Review the data preview for each step.

Question 2

Which TWO actions are required to set up a Power BI deployment pipeline with separate data sources for Development and Production?

Accepted Answer

Define dataset parameters in Power BI Desktop for data source values.. Defining dataset parameters in Power BI Desktop for data source values allows you to make the data source connection dynamic. These parameters can then be overridden at each stage of the deployment pipeline, enabling separate data sources for Development and Production without modifying the report file.

Answer

Assign the dataset owner to each stage workspace.

Answer

Re-enter data source credentials for each stage after deployment.

Answer

Create separate gateways for each stage.

Question 3

You are modeling a many-to-many relationship between 'Students' and 'Courses' via a junction table 'Enrollments'. You need to create a measure that counts the number of students enrolled in at least one course. The relationship between Students and Enrollments is one-to-many, and between Courses and Enrollments is one-to-many. What DAX measure should you use?

Accepted Answer

DISTINCTCOUNT(Students[StudentID]). DISTINCTCOUNT(Students[StudentID]). This measure counts unique students, which correctly handles the many-to-many relationship because filters applied to 'Courses' propagate through 'Enrollments' to 'Students', ensuring only students with at least one enrollment are counted. Option A (COUNTROWS(Enrollments)) counts enrollment rows, potentially double-counting students with multiple courses. Option B (COUNT(Courses[CourseID])) counts courses, not students. Option C (COUNTA(Students[StudentID])) counts all non-blank StudentIDs regardless of enrollment, missing the condition. DISTINCTCOUNT is the proper DAX function for distinct counts.

Answer

COUNTROWS(Enrollments)

Answer

COUNT(Courses[CourseID])

Answer

COUNTA(Students[StudentID])

Question 4

You are building a star schema in Power BI. Your fact table contains sales data at the transaction level. Which of the following is the best practice for modeling the date dimension to support time intelligence functions like year-to-date (YTD) calculations?

Accepted Answer

Create a date table with a contiguous range of dates and mark it as a date table. In Power BI, to enable time intelligence functions (like YTD, QTD, etc.), a dedicated date table with a contiguous range of dates is required. This table must be marked as a date table in the model. Option A is incorrect because using the fact table's date column directly lacks the necessary date hierarchy and attributes. Option B is incorrect because a date table that only includes dates with transactions will have gaps, leading to incorrect time intelligence calculations. Option C is incorrect because having multiple date columns in the fact table is not a replacement for a proper date dimension; instead, role-playing dimensions should be used. Option D is correct as it describes the best practice: a contiguous date table marked as a date table.

Answer

Use the fact table's date column directly in measures without a date table

Answer

Create a date table with only the dates that appear in the fact table

Answer

Use multiple date columns (e.g., OrderDate, ShipDate) in the fact table

Question 5

You have a Power BI model with a table 'Sales' that contains columns: Date, SalespersonID, and Amount. You have a 'Salespeople' table with columns: SalespersonID, Name, and Region. You need to create a measure that calculates the total sales amount for the current region, but only for salespeople who have made at least one sale in the current month. Which DAX expression achieves this?

Accepted Answer

SUMX(FILTER(Salespeople, CALCULATE(COUNTROWS(Sales), Sales[Date] >= DATE(YEAR(TODAY()), MONTH(TODAY()), 1)) > 0), CALCULATE(SUM(Sales[Amount]), Salespeople[Region] = SELECTEDVALUE(Salespeople[Region]))). It first filters the Salespeople table to only those who have made at least one sale in the current month (using COUNTROWS > 0 with a date filter), then iterates over that filtered list with SUMX, and for each salesperson calculates the sum of Amount filtered to their region using CALCULATE. Option A is wrong because it sums all sales in the selected region without any filter on salespeople who have sales this month. Option C is wrong because it sums over all salespeople without first filtering to those with current month sales, so it would incorrectly include salespeople with no current month sales. Option D is wrong because it sums sales only in the current month but does not restrict to salespeople with at least one sale in the current month; it would include all sales in that month, regardless of salesperson.

Answer

CALCULATE(SUM(Sales[Amount]), Salespeople[Region] = SELECTEDVALUE(Salespeople[Region]))

Answer

SUMX(Salespeople, CALCULATE(SUM(Sales[Amount]), Salespeople[Region] = SELECTEDVALUE(Salespeople[Region]), Sales[Date] >= DATE(YEAR(TODAY()), MONTH(TODAY()), 1)))

Answer

CALCULATE(SUM(Sales[Amount]), Salespeople[Region] = SELECTEDVALUE(Salespeople[Region]), Sales[Date] >= DATE(YEAR(TODAY()), MONTH(TODAY()), 1))

Question 6

You have a Power BI report that uses a custom visual from AppSource. The visual is not rendering correctly. Which three steps should you take to troubleshoot?

Accepted Answer

Check if the visual version is compatible with your Power BI Desktop version. Options B, C, and E are correct. Checking compatibility (B) ensures the visual supports your version of Power BI Desktop. Updating the visual (C) can fix known bugs. Verifying correct data fields (E) ensures the visual has the necessary input. Option A, disabling hardware acceleration, is a general troubleshooting step not specific to custom visuals. Option D, clearing browser cache, applies to Power BI Service, not Desktop.

Answer

Disable hardware acceleration in Power BI Desktop

Answer

Clear the browser cache

Question 7

Which THREE factors should you consider when designing a star schema for a Power BI semantic model? (Select three.)

Accepted Answer

Fact tables should contain measures and foreign keys to dimension tables.. The correct factors are: Fact tables should contain measures and foreign keys to dimension tables (A). Dimension tables should contain descriptive attributes and be denormalized (B). Avoid creating many-to-many relationships between dimensions; instead, use a bridge table when necessary (E). Option C is incorrect because fact tables should not be normalized; they should be denormalized to improve query performance. Option D is incorrect because calculated columns in dimension tables can increase model size and processing time; they are better placed as measures or in the fact table.

Answer

Fact tables should be normalized to reduce data duplication.

Answer

Use calculated columns in dimension tables to derive new attributes.

Question 8

You are a Power BI administrator for a large organization. A team has published a shared dataset to a Premium workspace. They use an XMLA endpoint to programmatically refresh the dataset daily. Recently, the refresh started failing with the error: 'The operation was canceled because the session was terminated by a concurrent operation.' The dataset is not partitioned. You need to ensure the refresh completes without errors. What should you do?

Accepted Answer

Enable the 'Refresh conflict detection' setting on the dataset to prevent concurrent operations.. The error 'The operation was canceled because the session was terminated by a concurrent operation' indicates that two refresh operations are conflicting on the same dataset. Enabling 'Refresh conflict detection' on the dataset prevents concurrent refreshes by queuing or blocking overlapping operations, ensuring the XMLA-triggered refresh completes without interruption.

Answer

Remove all scheduled refreshes and rely solely on the XMLA script.

Answer

Change the XMLA script to run less frequently, e.g., once per week.

Answer

Partition the dataset and refresh partitions sequentially.

Question 9

You have a measure as shown in the exhibit. The sales amount is not accumulating correctly; instead, it shows the total sales for all dates, regardless of the selected date filter. What is the problem?

Accepted Answer

The ALL('Date') function removes the filter context, so the calculation returns total sales for all dates.. Using ALL('Date') within CALCULATE removes the filter context on the Date table, causing the measure to return the total sales across all dates, not the current date context. Option A is incorrect; ALLEXCEPT would keep certain filters, but the problem here is specifically the removal of all date filters by ALL. Option C is incorrect; using MIN versus MAX in VAR SelectedDate does not cause the described behavior; the issue is the ALL function. Option D is incorrect; an inactive relationship would prevent proper filtering but would not result in the measure returning the total for all dates; the symptom would be different.

Answer

The measure should use ALLEXCEPT instead of ALL.

Answer

The VAR SelectedDate should be MIN instead of MAX.

Answer

The relationship between Sales and Date is inactive.

Question 10

You are using Power Query to combine data from multiple Excel files stored in a SharePoint Online document library. Each file has the same structure. You need to ensure that the query automatically includes new files added to the library without manual updates. Which approach should you use?

Accepted Answer

Use 'Get Data from SharePoint Online Folder' and then combine files using 'Combine & Transform Data'.. The 'Get Data from SharePoint Online Folder' connector in Power Query retrieves metadata for all files in the folder, and the 'Combine & Transform Data' action automatically applies a sample file transformation to all files. When new files are added to the library, refreshing the query will include them without manual intervention, as the connector dynamically reads the folder contents.

Answer

Use 'Get Data from Excel' and specify each file path manually.

Answer

Use 'Get Data from SQL Server' and write a query to read files.

Answer

Use 'Get Data from SharePoint Online List' and then expand the file content.

Question 11

Which TWO of the following are best practices for modeling many-to-many relationships in Power BI?

Accepted Answer

Use a bridge table to resolve the many-to-many relationship. Both using a bridge table and using a measure that iterates over it with SUMX are best practices for modeling many-to-many relationships in Power BI. A bridge table, when properly configured with many-to-many cardinality or CROSSFILTER, enables correct filtering. A SUMX measure over the bridge table ensures accurate aggregations. Setting cross-filter direction to both (Option B) can cause ambiguous filtering and performance issues. Composite models with DirectQuery (Option C) are not a specific best practice for this scenario. Creating a calculated table (Option E) does not properly resolve the relationship and often leads to data duplication.

Answer

Set cross-filter direction to both for all relationships

Answer

Use a composite model with DirectQuery for one of the tables

Answer

Create a calculated table that combines the two tables

Question 12

Which TWO of the following are valid ways to create a date table in Power BI?

Accepted Answer

Using DAX function CALENDAR or CALENDARAUTO.. The DAX functions CALENDAR and CALENDARAUTO are specifically designed to generate a single-column table of dates, which can then be used as a date table. CALENDAR requires explicit start and end dates, while CALENDARAUTO automatically scans the model to determine the date range. Both are standard methods for creating a date table in Power BI.

Answer

Using the time intelligence functions like TOTALYTD.

Answer

Marking an existing table as a date table.

Answer

Enabling the auto date/time feature.

Question 13

You are using Power Query to combine data from multiple CSV files in a folder. Each file has the same structure. You want to append all rows into a single table. Which Power Query function should you use?

Accepted Answer

Combine Files from the folder connector.. The 'Combine Files' transformation in Power Query is specifically designed to import and append multiple CSV files from a folder into a single table. When you connect to a folder using the 'From Folder' connector, Power Query automatically generates a 'Combine Files' step that uses the 'Table.Combine' function under the hood, which appends all rows from identically structured files into one unified table.

Answer

Group By.

Answer

Append Queries.

Answer

Merge Queries as new.

Question 14

You have a Power Query query that loads data from an OData source. You need to reduce the amount of data loaded into the data model. What is the best practice?

Accepted Answer

Apply a filter in Power Query before loading.. Applying filters in Power Query before loading data into the data model is the best practice for reducing data volume. Power Query pushes filters down to the OData source using OData query parameters (e.g., $filter), ensuring only the required rows are retrieved from the source. This minimizes network transfer and memory usage in the data model, aligning with the principle of early filtering in the ETL process.

Answer

Apply a filter in the data model using DAX.

Answer

Use 'Enable load' option to turn off loading for the query.

Answer

Load all data and then hide columns you don't need.

Question 15

You have a Power BI workspace that contains a report connected to an Azure Analysis Services (AAS) model. The data source uses Single Sign-On (SSO) with Microsoft Entra ID. When users access the report, they see an error that the data cannot be refreshed. What is the most likely cause?

Accepted Answer

The dataset is configured in Import mode.. The most likely cause is that the dataset is configured in Import mode. Single Sign-On (SSO) with Microsoft Entra ID is only supported when the dataset uses DirectQuery or Live Connection mode. Import mode requires stored credentials and does not pass the user's identity to the data source. Option A is incorrect because RLS does not affect data refresh connectivity. Option B is incorrect because stored credentials are not used when SSO is enabled. Option C is incorrect because SSO uses the user's identity, not a service principal.

Answer

Row-level security (RLS) is not configured on the AAS model.

Answer

The data source credentials are stored in the dataset.

Answer

The service principal used for authentication has expired.