PL-300 Practice Test 16 — 15 Questions

Question 1

You are modeling data for a retail company. You have a 'Transactions' fact table with millions of rows. You need to improve query performance for a report that filters by 'Store' and 'Date'. Which action will have the most impact?

Accepted Answer

Ensure the date table is marked as a date table and has a continuous date range.. Option C is correct because marking the date table improves time intelligence and performance. Option A is wrong because composite models add complexity. Option B is wrong because removing the date table would break time intelligence. Option D is wrong because merging tables increases size.

Answer

Merge the 'Store' and 'Transactions' tables into one.

Answer

Use a composite model with DirectQuery for the fact table.

Answer

Remove the date table and use the date column directly in the fact table.

Question 2

Which TWO actions can improve performance of a Power BI DirectQuery model?

Accepted Answer

Ensure proper indexing in the source database. Options A and D are correct. Reducing columns and increasing data source indexing improve query performance. Option B is wrong because bidirectional filtering often decreases performance. Option C is wrong because complex calculated columns slow queries. Option E is wrong because Import mode is not DirectQuery.

Answer

Switch the model to Import mode

Answer

Enable bidirectional cross-filtering on all relationships

Answer

Use calculated columns with complex logic

Question 3

You have a data model with a Sales table and a Date table. You create a measure: Total Sales = SUM(Sales[Amount]). When you add a slicer for Date[Year], the measure does not filter correctly. What is the most likely cause?

Accepted Answer

The relationship is inactive. Option D is correct because if the relationship is inactive, filters from the Date table won't propagate. Option A would cause a different error. Option B would give incorrect values. Option C is not a typical issue.

Answer

The Date table is not marked as a date table

Answer

The Sales table has no relationship to the Date table

Answer

The measure uses SUM instead of SUMX

Question 4

You have a Power BI data model with a Sales table and a Product table. You want to create a measure that calculates the percentage of total sales for each product category. Which DAX pattern should you use?

Accepted Answer

DIVIDE(SUM(Sales[Amount]), CALCULATE(SUM(Sales[Amount]), ALL(Product[Category]))). Option B is correct because DIVIDE(SUM(Sales[Amount]), CALCULATE(SUM(Sales[Amount]), ALL(Product[Category]))) calculates the percentage of total. Option A uses ALL(Product) which removes all filters on Product table. Option C uses ALLSELECTED which respects slicers. Option D uses REMOVEFILTERS on a column.

Answer

SUM(Sales[Amount]) / CALCULATE(SUM(Sales[Amount]), REMOVEFILTERS(Sales))

Answer

SUM(Sales[Amount]) / SUM(Sales[Amount])

Answer

DIVIDE(SUM(Sales[Amount]), CALCULATE(SUM(Sales[Amount]), ALLSELECTED()))

Question 5

Which TWO actions should you take when designing a data model that includes a fact table with a large number of rows and multiple dimension tables? (Select exactly 2.)

Accepted Answer

Use integer-based foreign keys in the fact table to link to dimension tables. Options A and C are correct. Option A: Using integer foreign keys reduces storage and improves join performance. Option C: Hiding the fact table from report view prevents users from accidentally querying it directly, promoting use of measures. Option B is wrong because creating calculated columns in the fact table can increase model size and degrade performance. Option D is wrong because default summarization is not recommended for fact tables; measures should be used instead. Option E is wrong because disabling auto date/time is a general best practice but not specific to large fact tables.

Answer

Create calculated columns in the fact table for additional attributes

Answer

Enable the Auto Date/Time feature for date columns

Answer

Set default summarization to 'Sum' for all numeric columns in the fact table

Question 6

You are designing a Power BI data model that includes a Sales table and a Product table. The Product table contains a column 'Category' with values like 'Electronics', 'Clothing', etc. You need to create a measure that calculates the total sales amount for the 'Electronics' category only. Which DAX expression should you use?

Accepted Answer

CALCULATE(SUM(Sales[Amount]), Product[Category] = 'Electronics'). Option D is correct. CALCULATE modifies filter context, and here it applies a filter on Product[Category] = 'Electronics'. Option A sums all sales without filter. Option B uses SUMX with a filter but is less efficient. Option C uses CALCULATE with FILTER, which is redundant.

Answer

SUM(Sales[Amount])

Answer

SUMX(FILTER(Sales, RELATED(Product[Category]) = 'Electronics'), Sales[Amount])

Answer

CALCULATE(SUM(Sales[Amount]), FILTER(Product, Product[Category] = 'Electronics'))

Question 7

You are creating a calculated table in Power BI that contains a list of unique products from the 'Sales' table. Which DAX function should you use?

Accepted Answer

DISTINCT(Sales[Product]). Option C is correct because DISTINCT returns a single column of unique values. Option A is wrong because VALUES returns unique values but includes blank if present. Option B is wrong because SUMMARIZE creates a table with multiple columns. Option D is wrong because ALL returns all rows, ignoring filters.

Answer

SUMMARIZE(Sales, Sales[Product])

Answer

VALUES(Sales[Product])

Answer

ALL(Sales[Product])

Question 8

Refer to the exhibit. The DAX measure 'Sales YTD' is defined as shown. The model has a Date table marked as a date table and a relationship to Sales[OrderDate]. However, the measure returns BLANK for all months except December. What is the most likely cause?

Accepted Answer

The Date table's year-end date is December 31, so YTD only shows data for December.. Option D is correct because DATESYTD uses the date table's year-end date, which by default is December 31. If the Date table's year ends in December, the YTD calculation only returns values for that month. Option A is wrong because the relationship is correctly configured. Option B is wrong because the measure uses the Date table column. Option C is wrong because the Date table is marked as a date table.

Answer

The measure uses 'Date'[Date] but the fact table uses 'Sales'[OrderDate].

Answer

The Date table is not marked as a date table.

Answer

The relationship between the Date table and Sales table is inactive.

Question 9

Refer to the exhibit. You apply the above RLS rule to a semantic model. The rule is intended to restrict sales data by the user's region, which is stored in the user's email domain (e.g., user@west.contoso.com). However, the rule does not filter any rows. What is the most likely issue?

Accepted Answer

The filter expression compares the full UPN to the Region column, which likely contains only the region name.. Option B is correct because USERPRINCIPALNAME() returns the full UPN, which includes the domain. The filter expression compares the entire UPN to the Region column, which likely contains only the region part (e.g., 'West'). Option A is wrong because the rule is applied. Option C is wrong because the table exists. Option D is wrong because USERPRINCIPALNAME() is valid.

Answer

The Sales table does not have a Region column.

Answer

USERPRINCIPALNAME() is not available in the current Power BI version.

Answer

The RLS rule is not applied to the semantic model.

Question 10

You have two tables: 'Orders' and 'Customers'. You want to create a relationship where each order is linked to one customer, but a customer can have many orders. Which cardinality should you choose?

Accepted Answer

Many-to-one (*:1) from Orders to Customers. Option A is correct because one-to-many from Customers to Orders is the natural direction. Option B is reverse. Option C is wrong because many-to-many is not appropriate. Option D is wrong because one-to-one is too restrictive.

Answer

Many-to-many (*:*)

Answer

One-to-many (1:*) from Orders to Customers

Answer

One-to-one (1:1)

Question 11

You need to create a calculated column that categorizes products as 'Low', 'Medium', or 'High' based on the 'UnitPrice' column. Which DAX function should you use?

Accepted Answer

SWITCH. Option B is correct because SWITCH evaluates conditions sequentially. Option A is wrong because IF can only handle two outcomes. Option C is wrong because CALCULATE modifies filter context, not for categorization. Option D is wrong because SUM is for aggregation.

Answer

CALCULATE

Answer

SUM

Answer

IF

Question 12

Refer to the exhibit. You apply the row-level security (RLS) policy shown to the Sales table. Which rows will be visible to users?

Accepted Answer

Only rows where Amount > 1000. Option B is correct because the filter only includes rows where Amount > 1000. Option A is wrong because it includes all rows. Option C is wrong because it includes less. Option D is wrong because it excludes the condition.

Answer

Rows where Amount is not blank

Answer

All rows in the Sales table

Answer

Only rows where Amount <= 1000

Question 13

You have a Power BI data model with a table that contains duplicate rows. You want to remove duplicates in Power Query. Which transformation should you use?

Accepted Answer

Remove Duplicates. Option C is correct because 'Remove Duplicates' removes duplicate rows based on selected columns. Option A filters rows. Option B groups rows. Option D replaces values.

Answer

Replace Values

Answer

Filter Rows

Answer

Group By

Question 14

You have a Power BI model with a fact table and several dimension tables. You need to ensure that when a filter is applied to a dimension table, it also filters related rows in other dimension tables through the fact table. Which type of relationship direction should you configure?

Accepted Answer

Both. Option B is correct because cross filter direction set to 'Both' allows filters to propagate in both directions, enabling dimension tables to filter each other through the fact table. Option A is wrong because 'Single' only filters from the one side to the many side. Option C is wrong because 'None' disables cross filtering. Option D is wrong because 'Automatic' is not a valid setting in Power BI.

Answer

Automatic

Answer

None

Answer

Single

Question 15

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. Options A, C, and D are correct. Option A: Using single-direction cross-filtering is generally recommended to avoid ambiguity and performance issues. Option C: Hiding foreign key columns in dimension tables prevents confusion and accidental use in visuals. Option D: Ensuring data types match between related columns is essential for relationship creation. Option B is wrong because many-to-many relationships should be avoided when possible; they can be complex and impact performance. Option E is wrong because bidirectional filtering is not typically recommended; it can cause ambiguous filtering and performance degradation.

Answer

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

Answer

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