What is the difference between setting the privacy level of a data source to None and Public?

[HamidBee]

I have a report that uses some Excel data, Ebay data and Amazon data. There are numerous transformation queries also. The authentication method I used is anonymous and so the privacy levels are currently set to 'None'. What is the difference between setting the privacy level of a data source as 'None' and 'Public'. What are the pros and cons?.

Thanks in advance.

[andyclap]

For future reference: It's reasonably well explained by the document linked by HamidBee https://www.alphabold.com/data-privacy-settings-in-power-bi/

The difference between None and Public appears when you introduce a query that merges tables from different sources.

On the PowerBI service, if the level of the data source on one side of the merge is None (the default) the merge will fail with the error:

Information is needed in order to combine data. Please specify a privacy level for each data source.

This is because the query optimiser may send data from one data source to the other datasource, e.g. the set of keys that need to be looked up for the merge. This could be sensitive data, so you have to tell the PowerBI service that the data source allows this.

As the optimiser can choose which side to source the keys from, and which to pass the keys to, both data sources involved in the merge need to be considered.

The behaviour is:

• None - no data sharing allowed, merges will fail with the above error.
• Private - no data sharing allowed, merges will try and work around this by loading all data.
• Organizational - data sharing allowed only if both sources can be traced back to the same organization tenant (difficult where you can't set the organization for a source, e.g. your own cloud database).
• Public - data sharing allowed, data from this source can be passed to any other source.

It's unfortunate this setting is not well named (I originally assumed this controlled the datasource visibility, e.g. making it publicly available!) and the built-in documentation doesn't clarify the exact usage.

[Anonymous]

Hi @HamidBee ,

NONE :

This is the default Privacy Level set to each data source when it is first queried in Power BI. If the report has only one data source, there is no need to change this privacy level because there is no risk of exposing data between various sources. However, as soon as a second data source is created in the report, Power BI asks for the privacy level to be determined for both the data sources because it cannot be kept to None now. The privacy levels need to be determined before Power BI proceeds further. 

PUBLIC :

The name says it all. There is no security for this Privacy Level. The data from a public source can be passed to other sources as part of Query Folding. There are no restrictions upon this data source, and it gives the best performance when combined with the benefits of Query Folding. However, you need to be completely sure that there are no security concerns with marking a data source as Public.

Please refer to the following document for more information.

Data Privacy Settings in Power BI (Business Intelligence) (alphabold.com)

The Inheritance Of Data Privacy Settings And The None Data Privacy Level

Set privacy levels (Power Query) - Microsoft Support

Best Regards,

Neeko Tang

If this post  helps, then please consider Accept it as the solution  to help the other members find it more quickly. 

[HamidBee]

This has been copied word for word on this website:

https://www.alphabold.com/data-privacy-settings-in-power-bi/

WIth regards to: "However, as soon as a second data source is created in the report, Power BI asks for the privacy level to be determined for both the data sources because it cannot be kept to None now."

I personally tried to do this. I created a report with two different sources. I used anonymous to access both sources. Both privacy levels are set to 'None'. I never got any sort of prompt from Power BI asking me to change the privacy level from 'None'.Can you please explain this further?.

[Anonymous]

Hi @HamidBee ,

According to my tests, connecting to a data source and saving when setting the privacy level to none, and then connecting to a data source does not prompt you about the privacy level. When you connect to a data source and set the privacy level to none, save and publish, and then connect to the dataset using desktop, and then connect to a data source, the following prompt will pop up.

According to known documentation, the public privacy level is only supported for file, Internet data source, or workbook data, so the privacy level is set to None or Public is the same for all three data sources. For other data sources, selecting a privacy level of None means that the data is insecure.

Best Regards,

Neeko Tang

If this post  helps, then please consider Accept it as the solution  to help the other members find it more quickly.