In addition to the authentication method and user credentials for a data source, Power BI also stores a privacy level for each data source. Privacy levels define the isolation level of data sources and thus restrict the integration of data sources in M queries.
For example, in the absence of privacy levels, an M query that merges a CSV file with a publicly available online database could result in the data from the CSV file being passed to the online database to execute the operation. Although this default behavior is preferable from a query performance and resource utilization standpoint, the CSV file may contain sensitive information that should never leave the organization or even an individual user's machine. Applying ...
