Regarding there is no defined relationship defined yet message while managing relationship

Hi  Kiruthiga,
Thank you for reaching out to the Microsoft Fabric Forum Community. 

Thank you rohit1991 lbendlin, for your helpful insights.

To address the "no defined relationship" issue, creating bridge tables is an effective approach. Since Table1 contains duplicate keys (due to the granularity of Brand, PG, and Segment), it cannot be used directly in a one-to-many relationship with Table2 and Table3, which have unique keys.  

While this approach is effective, there are some limitations you should be aware of:  

• Adding bridge tables increases the complexity of your data model. You'll need to manage additional relationships, which could become harder to maintain as your model grows.  
• The added relationships and more complex DAX queries could lead to slower performance, especially with large datasets.  
• If relationships aren't correctly configured, it may lead to issues with filter propagation, causing inaccurate data. Ensure all relationships are set up properly and use DAX functions like USERELATIONSHIP if needed.  
• Ensure your bridge tables contain only distinct values. If duplicates are present, it could impact the accuracy of your results.  
• Be cautious of introducing many-to-many relationships, as they require careful management and may necessitate advanced DAX for correct behavior.  

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Thank you