What is relationship direction in Power BI?

< 1 min read

Relationship direction defines how filters move between tables in the data model.
In my sales dashboard, Date filtered Sales through a single direction relationship.
That means when I selected a month, only the fact table got filtered, not the dimension back.
Single direction keeps performance faster and avoids ambiguous filter paths.
Bi-directional allows both tables to filter each other, useful in many-to-many cases.
For example, Customer ↔ Product bridge needed both direction to show correct selections.
But it created wrong totals in some visuals due to circular filtering.
So I used single direction by default and enabled bi-directional only when necessary.
This kept numbers accurate and improved report refresh performance.

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