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Microsoft Idea

Power BI


Virtual Junk Dimensions

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Konstantin Volke's profile image

Konstantin Volke on 09 Jan 2023 09:25:11

Junk dimensions are a good way to create a dimension with several flags. (e.g. Understand star schema and the importance for Power BI - Power BI | Microsoft Learn)

However they are difficult to maintain, especially on the fact side. The alternative is to have a dimension per flag or attribute. This diverts from the main design objective to consolidate many flags in one dimension for usability reasons.

I propose the idea to have the ability to create a virtual table that groups just attributes from phyiscal tables. It is like an addition to perspectives or culutures which also just serve the User Experience and does not affect executes DAX in any way.

Here is an example: I have 3 physical dimensions which are loaded into the model:

Dimension Flag Great Customer

Dimension Flag Fast Shipping

Dimension Flag Order Returned

They all are connected to a Sales Fact.

However, it's a coorporate model with dozens of dimensions. I want to consolidate (for the user) but I don't want to introduce further complexitiy (for the ETL).

A "virtual" Junk Dimension comes in handy:

All columns from three dimensions are grouped into one virtual table e.g. called "Dimension Shipping Attributes". The physical relationships remain untouched. One cannot create relationships etc. Its just a presentation layer.

Best regards,