Testing RLS in Desktop in Power BI - Cell-by-Cell Formula Trace

Sample Data

Sales data by user and region to test Row-Level Security (RLS) in Power BI Desktop.

Cell	Value
A1	User
B1	Region
C1	Sales
A2	Alice
B2	North
C2	1000
A3	Bob
B3	South
C3	1500
A4	Charlie
B4	East
C4	1200

Formula Trace

CALCULATE(SUM(Sales[Sales]), USERNAME() = Sales[User])

Step 1: USERNAME()

Step 2: Sales[User] = "Alice"

Step 3: SUM(Sales[Sales]) filtered by User = 'Alice'

Step 4: CALCULATE(SUM(Sales[Sales]), USERNAME() = Sales[User])

Cell Reference Map

     A       B       C
  +-------+-------+-------+
1 | User  | Region| Sales |
  +-------+-------+-------+
2 | Alice | North | 1000  |
  +-------+-------+-------+
3 | Bob   | South | 1500  |
  +-------+-------+-------+
4 | Charlie| East | 1200  |
  +-------+-------+-------+

Filter references Sales[User] column (A2:A4) and Sales[Sales] column (C2:C4). USERNAME() returns current user.

The formula uses the User column to filter rows matching the current user and sums the Sales column.

Result

     D
  +-------+
1 | Sales |
  +-------+
2 | 1000  |
  +-------+

The result shows total sales for the logged-in user 'Alice', which is 1000.

Sheet Trace Quiz - 3 Questions

What does USERNAME() return in this formula?

A The region name

B The total sales amount

C The current logged-in user name

D The sum of all users

Key Result

CALCULATE with USERNAME() filters rows to current user and sums sales.

Practice

1. What is the main purpose of using View as Roles in Power BI Desktop?

easy

A. To preview how data looks for different user roles with Row-Level Security applied

B. To create new data tables in the model

C. To export reports to PDF format

D. To refresh data from the source

Solution

1. Step 1: Understand the function of 'View as Roles'

   This feature lets you simulate the data view of different security roles without publishing the report.

2. Step 2: Identify the purpose in context

   It helps verify that Row-Level Security (RLS) filters are working correctly by showing what data each role can access.

3. Final Answer:

   To preview how data looks for different user roles with Row-Level Security applied -> Option A

4. Quick Check:

   View as Roles previews RLS effects [OK]

Hint: Use 'View as Roles' to test RLS before publishing [OK]

Common Mistakes:

• Confusing 'View as Roles' with data refresh
• Thinking it creates new tables
• Assuming it exports reports

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

easy

A. Sales[Region] = "West"

B. FILTER(Sales, Sales[Region] = "West")

C. Sales[Region] == "West"

D. Sales.Region = 'West'

Solution

1. Step 1: Recall DAX filter syntax for roles

   Role filters use a Boolean expression like Table[Column] = "Value" to filter rows.

2. Step 2: Evaluate each option

   Sales[Region] = "West" uses correct DAX syntax with single equals and double quotes. FILTER(Sales, Sales[Region] = "West") is a function, not a direct filter expression. Sales[Region] == "West" uses double equals which is invalid in DAX. Sales.Region = 'West' uses dot notation and single quotes, which is incorrect.

3. Final Answer:

   Sales[Region] = "West" -> Option A

4. Quick Check:

   DAX role filter uses single equals and double quotes [OK]

Hint: Use single equals and double quotes in role filters [OK]

Common Mistakes:

• Using double equals (==) instead of single equals (=)
• Using dot notation instead of bracket notation
• Using FILTER function inside role filter

3. Given a role with filter Customers[Country] = "USA", what will COUNTROWS(Customers) return when viewing as this role if the Customers table has 100 rows with 30 from USA?

medium

A. 100

B. 70

C. 30

D. 0

Solution

1. Step 1: Understand the role filter effect

   The role filter limits visible rows to those where Country = "USA", so only 30 rows remain visible.

2. Step 2: Apply filter to COUNTROWS

   COUNTROWS counts only visible rows under the role filter, so it returns 30.

3. Final Answer:

   30 -> Option C

4. Quick Check:

   Role filter limits rows, COUNTROWS returns filtered count [OK]

Hint: COUNTROWS respects RLS filters, returns visible rows only [OK]

Common Mistakes:

• Ignoring role filter and returning total rows
• Confusing filtered out rows with visible rows
• Assuming COUNTROWS returns zero if filtered

4. You defined a role with filter Orders[Amount] > 1000 but when testing with 'View as Roles', all data is visible. What is the most likely cause?

medium

A. The role filter syntax is incorrect and ignored

B. The Orders table has no rows with Amount > 1000

C. The 'View as Roles' feature is disabled in Power BI Desktop

D. You did not assign the role to any user

Solution

1. Step 1: Check role assignment

   In Power BI Desktop, roles must be assigned to users in the service, but 'View as Roles' simulates roles without user assignment. However, if you select 'View as Roles' and no role is selected, no filter applies.

2. Step 2: Verify role filter syntax and data

   The syntax Orders[Amount] > 1000 is correct. If data had no matching rows, filtered data would be empty, not all visible.

3. Final Answer:

   You did not assign the role to any user -> Option D

4. Quick Check:

   Role must be selected in 'View as Roles' to apply filter [OK]

Hint: Select the role in 'View as Roles' to apply filters [OK]

Common Mistakes:

• Assuming syntax error when filter is correct
• Not selecting role in 'View as Roles' dialog
• Thinking 'View as Roles' is disabled by default

5. You have two roles: RoleA filters Sales[Region] = "East" and RoleB filters Sales[Region] = "West". How can you test combined access for a user assigned to both roles in Power BI Desktop?

hard

A. Create a new role with a filter combining both regions and test it

B. Use 'View as Roles' and select both RoleA and RoleB to see combined data

C. Assign the user only to RoleA and test, then switch to RoleB

D. You cannot test combined roles in Power BI Desktop

Solution

1. Step 1: Understand role combination in 'View as Roles'

   Power BI Desktop allows selecting multiple roles simultaneously in 'View as Roles'. The filters combine with OR logic, showing data accessible by any selected role.

2. Step 2: Apply multiple roles selection

   Selecting both RoleA and RoleB will show sales data from both East and West regions combined.

3. Final Answer:

   Use 'View as Roles' and select both RoleA and RoleB to see combined data -> Option B

4. Quick Check:

   Multiple roles combine filters with OR in 'View as Roles' [OK]

Hint: Select multiple roles in 'View as Roles' to test combined access [OK]

Common Mistakes:

• Thinking roles combine with AND logic
• Creating new roles unnecessarily
• Believing combined roles cannot be tested