PL-300 Quick Quiz — 10 Questions

Question 1

You are connecting to a data source that contains Personally Identifiable Information (PII). You need to ensure that only authorized users can view the data in Power BI reports. Which TWO actions should you take?

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

Accepted Answer

Define row-level security (RLS) roles in Power BI Desktop.. Row-Level Security (RLS) allows you to restrict data access at the row level based on user roles defined in Power BI Desktop. By creating roles and using DAX filters, you can ensure that only authorized users see specific rows of PII data when the report is published to the Power BI service and users are mapped to roles.

Answer

Enable encryption at rest for the dataset.

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Use Power Query to mask PII columns by replacing values with '***'.

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Apply sensitivity labels to the dataset.

Question 2

Which TWO DAX functions can be used to filter data in a measure?

Accepted Answer

FILTER. (FILTER) is correct because it is a DAX function specifically designed to return a filtered subset of a table based on a logical condition, making it a primary tool for row-level filtering within measures. Option E (CALCULATE) is correct because it modifies the filter context of a measure by applying or removing filters, effectively filtering data through its filter arguments. Both functions directly control which rows are included in calculations.

Answer

VALUES

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SUM

Answer

ALL

Question 3

You are reviewing a Power Query that imports data from SQL Server. The exhibit shows the M code. The SQL query filters records after a date, then Power Query filters rows with OrderQty > 10, and then groups by ProductID. What is a potential performance issue with this approach?

Accepted Answer

The filter on OrderQty > 10 should be included in the SQL query to reduce the amount of data transferred.. Pushing the `OrderQty > 10` filter into the SQL query reduces the amount of data transferred from SQL Server to Power Query. In Power Query, data is loaded into memory before transformations; filtering earlier in the source query minimizes memory usage and network latency, which is a key performance optimization in Power BI data loading.

Answer

The query will fail because the SQL query uses '>' with a string.

Answer

The SQL query should use a parameter for the date instead of a hardcoded value.

Answer

The grouping should be done in SQL to reduce data volume.

Question 4

Which TWO are best practices for optimizing Power Query performance? (Choose two.)

Accepted Answer

Disable the 'Enable background refresh' option in the query settings.. Disabling 'Enable background refresh' prevents Power Query from running queries in the background while you continue working in Power BI Desktop. This ensures that query execution is synchronous, which can improve performance by avoiding resource contention and allowing you to monitor progress directly. Background refresh can cause delays and unexpected behavior when multiple queries run simultaneously, especially with large data sources.

Answer

Merge tables as early as possible in the query to combine data.

Answer

Keep all columns in the table to avoid missing data.

Answer

Split columns by delimiter to normalize data.

Question 5

You have a Power BI report that uses a date table connected to a fact table. You need to ensure that all dates in the fact table are covered by the date table. Which relationship property should you configure?

Accepted Answer

Assume referential integrity. The 'Assume referential integrity' property, when enabled, tells Power BI that every value in the foreign key column of the fact table exists in the primary key column of the date table. This ensures that all dates in the fact table are covered by the date table, allowing Power BI to use more efficient storage and query execution (e.g., INNER JOIN semantics) rather than a full OUTER JOIN.

Answer

Make this relationship active

Answer

Cardinality

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Cross filter direction

Question 6

You are troubleshooting a Power Query transformation that groups sales data by ProductID. The query runs slowly and you suspect the filter is being applied after loading all rows. What change would improve performance by pushing the filter to the source?

Accepted Answer

Replace the first three lines with a native SQL query that includes the WHERE clause. Pushing filter logic to the source database via a native SQL query with a WHERE clause reduces the amount of data loaded into Power Query. This leverages query folding, which allows the source (e.g., SQL Server) to perform the filtering before data is transferred, significantly improving performance for large datasets.

Answer

Disable the 'Enable load' option for the SalesTable

Answer

Use CALCULATE in DAX to filter

Answer

Add a 'Table.Buffer' step after the filter

Question 7

Which THREE of the following are best practices for optimizing data load performance in Power BI?

Accepted Answer

Remove unnecessary columns and rows during the import process.. Removing unnecessary columns and rows during the import process reduces the amount of data loaded into the Power BI data model, which directly decreases memory usage and refresh time. By filtering out irrelevant data early in Power Query, you minimize the data volume that must be processed and stored, leading to faster load performance.

Answer

Split a large fact table into multiple smaller fact tables.

Answer

Use DirectQuery mode instead of Import mode to reduce data load time.

Question 8

You are connecting to a SharePoint folder containing 100 Excel files. Each file has a similar structure but different column names. What is the best practice to combine these files into a single table while preserving the data?

Accepted Answer

Use Power Query's 'Combine Files' feature, selecting a sample file and promoting headers, then transforming column names to a standard set.. Power Query's 'Combine Files' feature is designed specifically for this scenario: it uses a sample file to infer the transformation logic (e.g., promoting headers), then applies that logic to all files in the folder. By transforming column names to a standard set within the sample file step, you ensure consistent column names across all files, preserving data integrity while combining them into a single table.

Answer

Load each file as a separate table and create relationships in the model.

Answer

Use Power Query's 'Merge Queries' to join all files into one table.

Answer

Use 'Append Queries' to stack all files, then rename columns manually.

Question 9

A company wants to create a Power BI report that shows sales performance by region. The data contains a table 'Sales' with columns: Date, Amount, RegionID, and ProductID. They also have a 'Regions' table with RegionID and RegionName. They want to display a matrix visual with RegionName on rows and Year on columns, with the sum of Amount as values. However, the report displays only 'RegionID' instead of 'RegionName'. What is the most likely cause?

Accepted Answer

There is no active relationship between the Sales and Regions tables.. If there is no active relationship between the Sales and Regions tables, Power BI cannot use the RegionName from the Regions table to filter or group the Sales data. Instead, it defaults to displaying the RegionID from the Sales table, which is the only related field available in the visual. An active relationship must exist between the two tables on the RegionID columns for RegionName to appear in the matrix.

Answer

The relationship is configured as many-to-many.

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The relationship direction is set to Both.

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The RegionID column in the Sales table is hidden.

Question 10

Which TWO of the following are valid DAX functions for time intelligence? (Select two.)

Accepted Answer

DATEADD. DATEADD is a valid DAX time intelligence function that shifts dates forward or backward by a specified number of intervals (days, months, quarters, years). TOTALYTD is also a valid time intelligence function that calculates the year-to-date value of an expression. Both are part of the dedicated time intelligence function set in DAX, which requires a properly marked date table with continuous dates.

Answer

RANKX

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CONCATENATEX

Answer

MINX