RLS stands for Row-Level Security, which is a feature in Power BI (and also in SQL Server Analysis Services) that allows you to restrict data access at the row level based on the user viewing the data. RLS helps ensure that users can only see the data that they are authorized to see, based on their role or other attributes.
Here's a detailed explanation of how RLS works:
- Role Definitions: In Power BI, you can define roles that represent different groups of users or different levels of access. For example, you might have a "Sales Manager" role and a "Sales Representative" role. Each role can have its own set of rules for data access.
- Security Filters: For each role, you can define security filters that determine which rows of data the users in that role can access. These filters are typically based on columns in your data model that contain information about the user or their permissions.
- Evaluation Context: When a user interacts with a report or dashboard in Power BI, the RLS rules are applied dynamically based on the user's role. This means that the user will only see the data that they are allowed to see, based on the security filters defined for their role.
- Data Masking: In addition to restricting access to rows of data, RLS can also be used to apply data masking, which allows you to obfuscate sensitive data so that it is not visible to users who are not authorized to see it. For example, you might use data masking to show only the last four digits of a credit card number to certain users.
- Integration with Active Directory: Power BI integrates with Active Directory, which allows you to use your existing security groups and user accounts to manage access to your reports and dashboards. This makes it easier to apply RLS based on your existing organizational structure.
Overall, RLS is a powerful feature in Power BI that allows you to control access to your data at a granular level, ensuring that users only see the data that they are authorized to see.