- A
In Power BI Desktop, define row-level security roles to restrict PII columns.
Why wrong: RLS restricts rows, not columns, and applies in reports, not data loading.
- B
Apply data masking in Power Query using Text.Start or Text.End functions.
Why wrong: This is possible but not leveraging the source masking.
- C
Install the on-premises data gateway and configure it to use the service account.
Why wrong: Gateway is already likely installed; masking issue is about permissions.
- D
In the data source settings, use a SQL Server account that has been granted the UNMASK permission to see masked data, but actually you need an account WITHOUT UNMASK to see masked data. Actually, correct: Configure the data source connection to use a user without the UNMASK permission so that dynamic data masking applies.
Correct. The account used by Power BI must not have UNMASK to see masked data.
Quick Answer
The correct answer is to configure the data source connection to use a SQL Server account without the UNMASK permission. This works because dynamic data masking in SQL Server is a server-side feature that automatically obfuscates designated columns in query results for any user who lacks the UNMASK permission; when Power BI connects with such an account, the masked values are returned directly into the dataset during refresh. On the Microsoft Power BI Data Analyst PL-300 exam, this scenario tests your understanding of how dynamic data masking integrates with Power BI’s import mode—a common trap is assuming you need a privileged account to see masked data, when in fact the opposite is true. Remember that UNMASK reveals the truth, so to see the mask, you must leave the permission off. A helpful memory tip: “No UNMASK, no unmasking—the mask stays on.”
PL-300 Prepare the data Practice Question
This PL-300 practice question tests your understanding of prepare the data. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are a data analyst for a healthcare organization. You have a Power BI dataset that imports patient data from an on-premises SQL Server database. The database contains personally identifiable information (PII). You need to ensure that all PII columns are obfuscated when the data is loaded into Power BI. You have already masked the columns in the source database using dynamic data masking. However, when you refresh the dataset in Power BI, the masked values are not appearing. What should you do?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
In the data source settings, use a SQL Server account that has been granted the UNMASK permission to see masked data, but actually you need an account WITHOUT UNMASK to see masked data. Actually, correct: Configure the data source connection to use a user without the UNMASK permission so that dynamic data masking applies.
Option D is correct because dynamic data masking (DDM) in SQL Server works by returning masked values to users who lack the UNMASK permission. When Power BI connects to the database using a SQL Server account without UNMASK, DDM automatically obfuscates the PII columns in the query results, so the masked data is loaded into Power BI. The current issue is that the connection account likely has UNMASK permission, which reveals the original unmasked data instead of the masked values.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
In Power BI Desktop, define row-level security roles to restrict PII columns.
Why it's wrong here
RLS restricts rows, not columns, and applies in reports, not data loading.
- ✗
Apply data masking in Power Query using Text.Start or Text.End functions.
Why it's wrong here
This is possible but not leveraging the source masking.
- ✗
Install the on-premises data gateway and configure it to use the service account.
Why it's wrong here
Gateway is already likely installed; masking issue is about permissions.
- ✓
In the data source settings, use a SQL Server account that has been granted the UNMASK permission to see masked data, but actually you need an account WITHOUT UNMASK to see masked data. Actually, correct: Configure the data source connection to use a user without the UNMASK permission so that dynamic data masking applies.
Why this is correct
Correct. The account used by Power BI must not have UNMASK to see masked data.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume dynamic data masking is automatically applied to all connections, but in reality it only applies when the connecting user does not have the UNMASK permission, so the correct fix is to use a user without UNMASK rather than one with it.
Detailed technical explanation
How to think about this question
Dynamic data masking in SQL Server is a server-side feature that rewrites the query results at the column level based on the user's UNMASK permission. When Power BI imports data, it executes a SELECT statement; if the connection user lacks UNMASK, the database engine applies the masking rules defined in the schema (e.g., partial, default, or random masking) before returning the result set. A common subtlety is that DDM does not encrypt the data at rest; it only obfuscates the output for unauthorized users, so the underlying data remains intact in the database.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this PL-300 question test?
Prepare the data — This question tests Prepare the data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: In the data source settings, use a SQL Server account that has been granted the UNMASK permission to see masked data, but actually you need an account WITHOUT UNMASK to see masked data. Actually, correct: Configure the data source connection to use a user without the UNMASK permission so that dynamic data masking applies. — Option D is correct because dynamic data masking (DDM) in SQL Server works by returning masked values to users who lack the UNMASK permission. When Power BI connects to the database using a SQL Server account without UNMASK, DDM automatically obfuscates the PII columns in the query results, so the masked data is loaded into Power BI. The current issue is that the connection account likely has UNMASK permission, which reveals the original unmasked data instead of the masked values.
What should I do if I get this PL-300 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 24, 2026
This PL-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PL-300 exam.
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