Modification needed for text about multiple-column joins

[erapade]

You say: Avoid relationships on calculated columns. This guidance is relevant to databases where you need to do multi-column joins. Power BI today doesn't allow a relationship to be based on multiple columns as the FK/PK. The common workaround is to concatenate the columns together using a calculated column, and base the join on that column. While this workaround is reasonable for imported data, for DirectQuery, it results in a join on an expression. That result commonly prevents use of any indexes, and leads to poor performance. The only workaround is to actually materialize the multiple columns into a single column in the underlying database.

As I understand, Multi-column joins are still possible if they are done using none loading queries. So we can setup a query doing multi-column joins at the schematic Power Query level. Please let me know if you don't agree, as I find the wording "The only workaround is to actually materialize the multiple columns into a single column in the underlying database" not suggesting this would be possible

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Document Details

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• ID: 1ed1625f-12a2-5962-2959-696188711efe
• Version Independent ID: d8796367-6bd1-c63c-db86-59eb5a66c213
• Content: Using DirectQuery in Power BI - Power BI
• Content Source: powerbi-docs/connect-data/desktop-directquery-about.md
• Service: powerbi
• Sub-service: powerbi-desktop
• GitHub Login: @davidiseminger
• Microsoft Alias: davidi

[KesemSharabi]

Thanks for your comment, @erapade.

I've assigned this issue to the doc author for review.

[davidiseminger]

Thanks for the doc idea, and for the comment. We'll consider adding this to the documentation.