Which function should be used in the RLS role to match the users' Microsoft Entra ID login credentials with the emails in the RLS table column?

Using the USERPRINCIPALNAME function in the context of Row-Level Security (RLS) is essential for matching a user's Microsoft Entra ID (formerly Azure Active Directory) login credentials to the corresponding emails in the RLS table column. This function retrieves the user login name associated with the current user in the format of an email address or unique identifier, ensuring that the security roles are accurately mapped to the right user.

When implementing RLS, the goal is to control what data a user can access based on their identity. By using USERPRINCIPALNAME, you can dynamically filter data in Power BI reports, allowing users to only see data that pertains to their email or ID. This approach enhances security and data privacy by preventing unauthorized access to sensitive information.

In contrast, functions like NAMEOF do not directly relate to user identification in RLS, while TREATAS is typically used for modifying filter contexts in DAX calculations. USEROBJECTID is also related to user identification but operates differently than USERPRINCIPALNAME, which is specifically tailored for matching with email addresses used in RLS scenarios. Therefore, the choice of USERPRINCIPALNAME is appropriate for aligning user credentials with the RLS table's email data.