Relationships/Cardinality

Hi cingram11 ,

Thank you for reaching out to the Microsoft Fabric Community. Also responses provided by AlexisOlson  and speedramps  offer valuable insights, particularly around the concept of column cardinality and how it affects relationship design.

To add further clarity, in the context of Power BI and data modeling, a relationship defines how two tables are logically connected so that data from one table can filter or aggregate data in another. These relationships are governed by cardinality, which refers to how many rows in one table relate to rows in another.

Common types include one-to-one (1:1), one-to-many (1:M), and many-to-many (M:M). For instance, a one-to-many relationship is often created between a dimension table (e.g., Customers) and a fact table (e.g., Sales), where each customer can have many sales records, but each sale belongs to only one customer.

Column cardinality, as explained earlier, describes the number of distinct values in a column and plays a crucial role in determining the most efficient and correct relationship structure. For a detail information in relationship cardinality in Power BI, please refer to the document below: Model relationships in Power BI Desktop - Power BI | Microsoft Learn

Hope this helps. Please reach out for further assistance.
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Thank you.