Why RLS protects sensitive data in Power BI - Why Use It

Introduction

Row-Level Security (RLS) helps keep sensitive data safe by controlling who can see what in your reports. It stops users from seeing data they shouldn't by filtering data based on their identity.

When you want sales managers to see only their region's sales data in a report.

When HR wants to share employee data but restrict access to salary details by department.

When a company dashboard needs to show financial data only to executives, hiding it from other staff.

When you have a shared report but want each user to see only their own customer information.

When you want to comply with privacy rules by limiting data visibility based on user roles.

Steps

Step 1: Open

- Power BI Desktop

Your report file is ready for editing

Step 2: Click

- Modeling tab

Modeling options appear

Step 3: Select

- Manage Roles

The Manage Roles window opens

Step 4: Click

- Create

A new role is added for defining filters

Step 5: Type

- Role name box

Role is named (e.g., 'SalesRegion')

Step 6: Define

- Table filter DAX expression box

Filter expression limits data rows for this role

Step 7: Click

- Save

Role is saved and ready to test

Step 8: Use

- View as Roles

Report shows data as filtered by the selected role

Before vs After

Before

Report shows all sales data for all regions to every user

After

Report shows only sales data for the user's assigned region, hiding other regions

Settings Reference

Manage Roles

📍 Modeling tab > Manage Roles

Create and manage roles that filter data for users

Default: No roles defined

Role filter expression

📍 Manage Roles window > Table filter DAX box

Define which rows of data are visible for the role

Default: No filter (shows all data)

View as Roles

📍 Modeling tab > View as Roles

Preview report data as a user with a specific role

Default: No role selected

Common Mistakes

Not defining any filter expression for a role

The role will not restrict data and users will see all data

Always add a filter expression that limits data rows for the role

Testing RLS without using 'View as Roles'

You cannot confirm if the filters work correctly without previewing

Use 'View as Roles' to check what data each role can see

Assigning users to roles only in Power BI Desktop

User-role assignments happen in Power BI Service, not Desktop

Publish the report and assign users to roles in Power BI Service

Summary

RLS protects sensitive data by filtering report rows based on user roles.

You create roles with filter rules in Power BI Desktop and test them with 'View as Roles'.

Remember to assign users to roles in Power BI Service after publishing.

Practice

1. What is the main purpose of Row-Level Security (RLS) in Power BI?

easy

A. To speed up data refresh times

B. To change the visual design of the report for each user

C. To create new calculated columns automatically

D. To restrict data access by filtering rows based on the user's identity

Solution

1. Step 1: Understand RLS functionality

   RLS filters data rows so users only see data they are allowed to access.

2. Step 2: Compare options

   Speeding up refresh times, changing visual design, and creating calculated columns describe unrelated features; only restricting data access by filtering rows based on user identity matches RLS purpose.

3. Final Answer:

   To restrict data access by filtering rows based on the user's identity -> Option D

4. Quick Check:

   RLS filters rows by user identity = C [OK]

Hint: RLS controls data visibility per user, not report design [OK]

Common Mistakes:

• Confusing RLS with report formatting
• Thinking RLS speeds up data refresh
• Believing RLS creates new columns

2. Which of the following is the correct way to define a filter in a Power BI RLS role?

easy

A. FILTER('Sales', 'Sales'[Region] = "USERNAME()")

B. FILTER('Sales', 'Sales'[Region] == USERNAME())

C. FILTER('Sales', 'Sales'[Region] = USERPRINCIPALNAME())

D. FILTER('Sales', 'Sales'[Region] = USERNAME())

Solution

1. Step 1: Identify correct DAX function for user identity

   USERPRINCIPALNAME() returns the logged-in user's full username, commonly used in RLS filters.

2. Step 2: Check syntax correctness

   FILTER('Sales', 'Sales'[Region] = USERPRINCIPALNAME()) uses correct syntax and function. Using double equals (==), treating the function as a string, or using USERNAME() instead misuses syntax or less preferred function.

3. Final Answer:

   FILTER('Sales', 'Sales'[Region] = USERPRINCIPALNAME()) -> Option C

4. Quick Check:

   Use USERPRINCIPALNAME() for RLS filters = A [OK]

Hint: Use USERPRINCIPALNAME() for user-based filters in RLS [OK]

Common Mistakes:

• Using USERNAME() instead of USERPRINCIPALNAME()
• Using double equals (==) in DAX
• Putting USERNAME() inside quotes

3. Given this RLS filter on the 'Sales' table:
FILTER('Sales', 'Sales'[Salesperson] = USERPRINCIPALNAME())
If the logged-in user is '[e-mail]', what data will Alice see?

medium

A. All sales data regardless of salesperson

B. Only sales where 'Salesperson' equals '[e-mail]'

C. No data because USERPRINCIPALNAME() is invalid

D. Sales data for all salespersons except '[e-mail]'

Solution

1. Step 1: Understand the filter condition

   The filter keeps rows where 'Salesperson' matches the logged-in user's email.

2. Step 2: Apply the filter for user '[e-mail]'

   Only rows with 'Salesperson' = '[e-mail]' remain visible to Alice.

3. Final Answer:

   Only sales where 'Salesperson' equals '[e-mail]' -> Option B

4. Quick Check:

   RLS shows user-specific rows = B [OK]

Hint: RLS filters rows matching logged-in user exactly [OK]

Common Mistakes:

• Assuming all data is visible
• Thinking USERPRINCIPALNAME() is invalid
• Believing data for other users is shown

4. You created this RLS role filter:
FILTER('Orders', 'Orders'[Country] = USERNAME())
But users report seeing no data. What is the most likely issue?

medium

A. USERNAME() returns only the username, not the country name

B. FILTER function is not supported in RLS roles

C. The table name 'Orders' is misspelled

D. RLS roles cannot filter by text columns

Solution

1. Step 1: Understand USERNAME() output

   USERNAME() returns the user's login name, not a country name.

2. Step 2: Compare USERNAME() with 'Country' column

   Since 'Country' contains country names, the filter never matches, so no data shows.

3. Final Answer:

   USERNAME() returns only the username, not the country name -> Option A

4. Quick Check:

   Mismatch between USERNAME() and column values = A [OK]

Hint: Match USERPRINCIPALNAME() or correct user info to column values [OK]

Common Mistakes:

• Assuming USERNAME() returns country
• Thinking FILTER is unsupported in RLS
• Ignoring case sensitivity in filters

5. You want to protect sensitive sales data so that each regional manager sees only their region's data. Which approach best uses RLS to achieve this?

hard

A. Create a role with filter 'Sales'[Region] = LOOKUPVALUE('Managers'[Region], 'Managers'[Email], USERPRINCIPALNAME()) and assign managers by email

B. Do not use RLS; instead, create separate reports for each region

C. Create a role with filter 'Sales'[Region] = "Region1" and assign all managers to this role

D. Create a role with filter 'Sales'[Region] = USERPRINCIPALNAME() and assign managers their email as region

Solution

1. Step 1: Understand the need for dynamic filtering

   Each manager should see data for their assigned region, which may differ from their username.

2. Step 2: Use LOOKUPVALUE to map manager email to region

   Create a role with filter 'Sales'[Region] = LOOKUPVALUE('Managers'[Region], 'Managers'[Email], USERPRINCIPALNAME()) and assign managers by email uses LOOKUPVALUE to find the manager's region from a 'Managers' table, enabling correct filtering.

3. Step 3: Evaluate other options

   Create a role with filter 'Sales'[Region] = USERPRINCIPALNAME() and assign managers their email as region incorrectly assumes email equals region; C assigns all managers to one region; B avoids RLS and is less efficient.

4. Final Answer:

   Create a role with filter 'Sales'[Region] = LOOKUPVALUE('Managers'[Region], 'Managers'[Email], USERPRINCIPALNAME()) and assign managers by email -> Option A

5. Quick Check:

   Use LOOKUPVALUE for dynamic RLS filtering = D [OK]

Hint: Use LOOKUPVALUE to map users to their data dynamically [OK]

Common Mistakes:

• Assuming username equals region directly
• Assigning all users to one static region
• Avoiding RLS and duplicating reports