Forum Discussion
Cardinality issue with Many to Many Relationship
Hello,
I am currently having cardinality issues with a many to many relationship in Power BI. I have used opportunity number as the relationship, but now that i have done that it is messing up with my data.
Would anyone be able to help me with this issue?
thanks
1 Reply
Welcome to the club. Opportunity number or Sales Order Number or Order datetime are prime examples for what not to use as a join key . Their cardinality is just too high. For reference - the magic line is somewhere around 50k (yes, k, not M !!!)
Your best option is to not need that relationship. See if you can use TREATAS instead. Another option would be to pre-multiply the tables and thus eliminate the join. But that may not be possible if you don't have enough memory/compute.
Relationships in Power BI and Tabular models - SQLBI
Different options to model many-to-many relationships in Power BI and Tabular - SQLBI
