Object-level security (OLS) in Power BI is a feature that allows you to control which objects in a model users can see and interact with. This includes tables, columns, measures, and calculated columns. OLS is more granular than role-level security (RLS), which allows you to control which rows of data users can see in a report.

Examples:

• You can use OLS to hide sensitive columns from users, such as columns that contain personal data or financial information.
• You can use OLS to hide tables from users that they do not need to see, such as tables that contain historical data or data that is only used for internal purposes.
• You can use OLS to restrict users from interacting with certain objects, such as measures or calculated columns that are used for sensitive calculations.

OLS can be used in conjunction with RLS to create a powerful security solution for your Power BI reports. For example, you could use RLS to restrict which rows of data users can see in a report, and then use OLS to hide certain columns from users who do not need to see them.