Forum Discussion
Modelling Multi valued attributes in dimensions in Power BI
Hi vividvimu
Yes you can use bidirectional relationships if you ensure that There's only one path between tables no ambiguity and The cardinality supports it (i.e., 1:* between Student and others).
Student[Student Id] → Student Programs[Student Id] (One-to-Many, Bidirectional)
Student[Student Id] → Student Language Proficiency[Student Id] (One-to-Many, Bidirectional)
Using bidirectional filters is fine if you have only one clear path between the tables. Avoid Circular relationships & Multiple paths between two tables (Power BI will disable relationships or throw ambiguity errors)
Large datasets where bi-directionality can cause performance issues
If bidirectional filtering is not safe or causes issues, use the UNION + TREATAS technique.
Hi vividvimu
For attributes like programs, languages, and exam scores—where a single student can have multiple values—you’ll need a bridge table. For example:
Student → StudentProgramBridge ← Program
This bridge table should include composite keys (StudentID, ProgramID) and any relevant relationship attributes (e.g., start date, end date).
Since counselling sessions only link to StudentID, keep the direct relationship between Student and CounsellingSession. But if you need to filter counselling sessions by program, you can:
Use the bridge table in your DAX measures
Create a virtual relationship in DAX using TREATAS() or similar techniques
This keeps the model clean while allowing the filtering you need.
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Thank you.