PL-300 Practice Test 30 — 15 Questions

Question 1

A Power BI developer needs to model data from two sources: an on-premises SQL Server database and a cloud-based Salesforce instance. The developer wants to create a star schema in Power BI. Which approach should the developer use to combine the data?

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

Accepted Answer

Use Power Query in Power BI Desktop to import both sources and merge/append queries as needed.. Power Query in Power BI Desktop is the appropriate tool to import data from both an on-premises SQL Server database and a cloud-based Salesforce instance, allowing the developer to merge or append queries as needed to shape the data into a star schema. This approach supports combining disparate sources into a single import model, which is essential for creating a star schema with fact and dimension tables. Using Power Query ensures that all data is loaded into memory, enabling fast query performance and full modeling capabilities.

Answer

Use DirectQuery for both sources and create relationships in the model.

Answer

Use Power BI dataflows to ingest both sources and then reference them in a dataset.

Answer

Create a composite model using DirectQuery for SQL Server and Import for Salesforce.

Question 2

You are preparing data from multiple Excel files. Each file has a different structure; some have merged cells, empty rows, and inconsistent column names. Which TWO actions should you take to clean the data in Power Query? (Choose two.)

Accepted Answer

Remove blank rows that result from merged cells.. Option A is correct because merged cells in Excel often produce null or blank rows when imported into Power Query, and removing these blank rows (Home > Remove Rows > Remove Blank Rows) eliminates the structural noise so downstream transformations operate on valid records. Option E is correct because inconsistent column names across files typically mean the real headers are sitting in the first data row after import; using Home > Use First Row as Headers (Promote Headers) renames the columns correctly so each file's schema aligns before appending. Option B is not appropriate because grouping and summarizing is an aggregation step, not a cleaning step, and would collapse the detail rows needed for consolidation. Option C is not appropriate because merging columns creates a concatenated identifier, which does not address inconsistent names, blanks, or merged-cell artifacts. Option D is not appropriate because unpivoting is used to normalize wide/crosstab layouts into attribute-value pairs, which is unrelated to fixing headers or removing blank rows in this scenario.

Answer

Group rows by a key column to summarize data.

Answer

Merge columns to create a single identifier.

Answer

Unpivot columns to normalize the data.

Question 3

You are a Power BI developer for a financial services company. You are preparing data from multiple sources: a CSV file containing daily stock prices (ticker, date, close_price), a SQL Server database with company information (ticker, company_name, sector), and an Excel file with quarterly earnings data (ticker, quarter, earnings_per_share). The CSV file has 5 years of daily data (approx 1.3 million rows). The SQL Server table has 5000 rows. The Excel file has 20,000 rows. You need to create a data model that allows users to filter by sector, company, and date range, and to calculate moving averages of stock prices and compare earnings over time. Performance is critical. You must decide the best approach to combine and model this data. What should you do?

Accepted Answer

Import all tables, create a date table with CALENDAR, and establish relationships: StockPrices[Date] -> DateTable[Date], StockPrices[Ticker] -> Company[Ticker], Earnings[Ticker] -> Company[Ticker], and create a many-to-many relationship between Earnings and DateTable using a bridge table.. Importing all tables into the in-memory VertiPaq engine ensures optimal performance for large datasets (1.3M rows) and complex calculations like moving averages. Creating a separate date table with CALENDAR enables proper time intelligence, while the bridge table resolves the many-to-many relationship between quarterly earnings and daily dates, allowing accurate filtering by sector, company, and date range without performance degradation.

Answer

Use DirectQuery for StockPrices (CSV) and import the other tables.

Answer

Import only StockPrices and Company, and use the auto date/time feature; ignore Earnings data.

Answer

Import all tables, then in Power Query merge StockPrices with Company and Earnings into a single flat table using left outer joins.

Question 4

You are preparing data from an Azure SQL Database. You need to ensure that sensitive columns (e.g., Social Security Numbers) are obfuscated in Power BI reports. Which TWO of the following approaches can you use? (Choose two.)

Accepted Answer

Configure dynamic data masking on the Azure SQL Database.. Azure SQL Database Dynamic Data Masking (DDM) obfuscates sensitive data at the database query level, so when Power BI connects to the database, the masked values are automatically returned for unauthorized users. This is a server-side approach that does not require changes to the Power BI report or data model.

Answer

Use row-level security (RLS) in Power BI to hide sensitive columns.

Answer

Use Microsoft Purview sensitivity labels to mask data.

Answer

Apply column-level security in Power BI Desktop.

Question 5

You manage a Power BI workspace used by the sales team. After updating a dataset with new columns, some users report that their reports show old data. You verify that the scheduled refresh completed successfully. What should you do first?

Accepted Answer

Open the report in Power BI Desktop, refresh the dataset, and republish.. When a dataset is updated with new columns in Power BI Desktop, the report's underlying data model must be refreshed and republished to the Power BI service. Even if the scheduled refresh completes successfully, it only refreshes the existing data structure; it does not automatically incorporate schema changes like new columns. Republishing the .pbix file ensures the service has the updated metadata and data.

Answer

Clear the users' browser cache.

Answer

Reconfigure the scheduled refresh to run more frequently.

Answer

Reset the on-premises data gateway.

Question 6

You have a Power BI model with a fact table 'Sales' and a dimension table 'Product'. The Product table contains columns: ProductID, ProductName, Category, and Subcategory. You want to create a hierarchy for drill-down in reports: Category > Subcategory > ProductName. What is the correct way to define this hierarchy?

Accepted Answer

In Model view, right-click 'Category' > 'Create hierarchy', then add Subcategory and ProductName as levels.. Power BI's Model view allows you to create a hierarchy by right-clicking a column (e.g., Category) and selecting 'Create hierarchy', then adding Subcategory and ProductName as child levels. This defines a natural drill-down path for visuals, enabling users to navigate from Category to Subcategory to ProductName without modifying the data model or using workarounds.

Answer

In Power Query, merge the Category, Subcategory, and ProductName columns into one.

Answer

Create a calculated column using CONCATENATE to combine the levels.

Answer

In Report view, add all three columns to a visual's Values well.

Question 7

You are cleaning data in Power Query. A column contains customer names with inconsistent capitalization (e.g., 'john smith', 'JANE DOE'). You need to standardize the names to proper case (first letter uppercase, rest lowercase). Which transformation should you use?

Accepted Answer

Use 'Format' > 'Capitalize Each Word'.. The 'Capitalize Each Word' transformation in Power Query converts the first letter of each word to uppercase and the rest to lowercase, which is exactly what proper case requires. This is the correct choice because it directly addresses the need to standardize inconsistent casing (e.g., 'john smith' becomes 'John Smith', 'JANE DOE' becomes 'Jane Doe').

Answer

Use 'Format' > 'Trim'.

Answer

Use 'Format' > 'Lowercase'.

Answer

Use 'Format' > 'Uppercase'.

Question 8

Which THREE of the following are best practices for designing Power BI reports for accessibility? (Select three.)

Accepted Answer

Ensure tab order is logical for keyboard navigation.. Option B is correct because a logical tab order lets keyboard and screen-reader users move through report elements in a meaningful sequence, which is a core accessibility requirement in Power BI. Option C is correct because high color contrast between text and background ensures content remains legible for users with low vision or color-vision deficiencies, aligning with WCAG contrast guidance. Option E is correct because alt text gives screen readers a textual description of visuals, charts, and images so non-visual users can understand the data being presented. Option A is not appropriate because 3D effects reduce clarity and can distort data perception rather than improve accessibility. Option D is not appropriate because using as many colors as possible harms differentiation for color-blind users and creates visual clutter; accessible designs use a limited, distinguishable palette.

Answer

Use 3D effects to make visuals more engaging.

Answer

Use as many colors as possible to differentiate data.

Question 9

A data model contains a table 'Sales' with columns: Date, ProductID, Quantity, Amount. There is a 'Products' table with columns: ProductID, ProductName, CategoryID. A measure 'Total Sales' = SUM(Sales[Amount]) returns correct values. However, when a user creates a visual with CategoryID from 'Products' and 'Total Sales', some categories show blank. What is the most likely cause?

Accepted Answer

There are ProductID values in Sales that do not exist in Products table.. When ProductID values in the Sales table do not have matching entries in the Products table, the relationship between the two tables will result in blank CategoryID values for those unmatched rows. In Power BI, a many-to-one relationship (the default) filters from the 'one' side (Products) to the 'many' side (Sales), but if a Sales row has a ProductID not present in Products, it cannot be matched, and any column from Products (like CategoryID) will appear as blank in visuals. This is a classic data integrity issue where the fact table contains orphaned foreign keys.

Answer

The 'Total Sales' measure is not properly referencing the Sales table.

Answer

The relationship between Sales and Products is set to many-to-one, single direction.

Answer

The relationship is set to both directions (bidirectional).

Question 10

You are reviewing a Power Query M script used to create a table in Power BI. The script imports data from SQL Server, filters for orders in 2022, groups by ProductID to sum revenue, sorts descending, and takes the top 10. However, the table loads slowly. You need to improve performance. Which change should you make?

Accepted Answer

Modify the script to use a native SQL query that performs the filtering and aggregation on the server side.. Pushing filtering, grouping, and aggregation to SQL Server via a native query reduces the volume of data transferred to Power BI and leverages the database engine's optimized execution. This minimizes memory and processing overhead in Power Query, directly addressing the slow load time caused by performing these operations on imported data.

Answer

Add a Table.Buffer step before the filter to speed up subsequent operations.

Answer

Remove the sorting step because it is unnecessary for the final table.

Answer

Combine the filter, group, and sort into a single step using Table.Buffer.

Question 11

You need to audit Power BI activities such as viewing reports, sharing dashboards, and exporting data. Which TWO actions should you take to enable and access audit logs? (Choose two.)

Accepted Answer

Access the audit log from the Microsoft 365 compliance portal.. To audit Power BI activities, you must first enable audit logging by turning on the 'Create audit logs for Power BI activities' tenant setting in the Power BI admin portal (option C). Once enabled, you can access the audit logs from the Microsoft 365 compliance portal (option B). Option A is incorrect because Microsoft Defender for Cloud Apps is not the primary location for audit logs; it can integrate but is not required. Option D is incorrect because Power BI does not have an export feature for audit logs to CSV; you can export from the compliance portal. Option E is incorrect because Azure Monitor diagnostic settings are for Azure resources, not for Power BI audit logs.

Answer

Configure Microsoft Defender for Cloud Apps to forward logs to Microsoft Sentinel.

Answer

Use the 'Export' feature in Power BI to export audit logs to a CSV file.

Answer

Set up a diagnostic setting in Azure Monitor to collect Power BI logs.

Question 12

You are connecting to an Azure SQL Database from Power BI Desktop. The database contains a view that returns thousands of rows. You only need the last 100 rows for analysis. What is the most efficient way to reduce the data loaded?

Accepted Answer

Use the 'Keep Top Rows' transformation in Power Query after applying a sort. It uses Power Query's 'Keep Top Rows' transformation after sorting the view by the desired order (e.g., descending on a date column). This approach pushes the sort and row-limiting logic to the source database via query folding, ensuring only the last 100 rows are transferred over the network, which is the most efficient method for reducing data loaded.

Answer

Write a native SQL query with a WHERE clause to limit rows

Answer

Use DirectQuery mode and add a filter in the report

Answer

Import all rows and then remove rows in Power Query

Question 13

Which are valid ways to create a calculated table in Power BI? (Select all that apply)

Accepted Answer

VALUES(Customer[Country]). To create a calculated table, you need a DAX expression that returns a table object. Options A, C, D, and E all return tables: VALUES returns a single-column table of distinct values; FILTER returns a filtered subset of rows; CALENDARAUTO returns a date range table; SUMMARIZE returns a grouped table with aggregations. Option B, CALCULATE, returns a scalar value, not a table, so it is invalid.

Answer

CALCULATE(SUM(Sales[Amount]), ALL(Sales))

Question 14

Which THREE are best practices for managing relationships in Power BI? (Select exactly 3.)

Accepted Answer

Hide foreign key columns in dimension tables to prevent misuse. Option B is correct because hiding foreign key columns in dimension tables keeps the model clean and prevents report authors from accidentally using these technical keys in visuals instead of the proper dimension attributes. Option C is correct because single-direction cross-filtering is the default and preferred approach; bidirectional filtering should only be enabled when a specific requirement demands it, since it can introduce ambiguity, performance degradation, and unexpected results. Option E is correct because related columns must share the same data type for the relationship to be created and to filter correctly; mismatched types cause errors or force Power BI to create an inactive relationship. Option A is incorrect because many-to-many relationships should be avoided when possible, as they complicate the model, can produce ambiguous results, and are harder to optimize. Option D is incorrect because setting all relationships to bidirectional cross-filtering is not a best practice; it can create ambiguous filter paths, circular dependencies, and performance issues.

Answer

Use many-to-many relationships whenever possible to simplify the model

Answer

Always set cross-filter direction to both to allow full interactivity

Question 15

You are a data analyst for a multinational corporation. You are building a Power BI report that uses a large fact table (100 million rows) and several dimension tables. The data source is a SQL Server data warehouse. Users need to see near real-time data with a maximum latency of 15 minutes. The current import mode takes too long to refresh. You decide to use DirectQuery mode. However, queries are slow. You need to improve query performance. You consider creating aggregations in the data source. Which approach should you take in Power BI to leverage these aggregations?

Accepted Answer

Define aggregations in Power BI on the DirectQuery tables.. Power BI allows you to define aggregations on DirectQuery tables, which enables the engine to route queries to pre-aggregated data at the source (e.g., SQL Server indexed views or materialized views) when possible, significantly reducing query latency. This approach leverages the existing aggregations in the data source without changing the storage mode or importing data, maintaining near real-time freshness with a 15-minute latency requirement.

Answer

Create a composite model with an imported aggregated table.

Answer

Change the storage mode to Import for the fact table.

Answer

Create a SQL Server view that aggregates data and use it as the source.