Map two or more tables, while there is no unique column to relate

[DryMouse555]

Hi,

I have imported 4 tables, and all the tables are not related. I mean there is no unique column to map. If I map, it gives many to many relationships.
Is there a way I can map them efficiently and create a better relationship like one-to-one or one-to-many?

Thanks,

[v-jingzhan-msft]

Hi @DryMouse555 

One method is to create bridge tables as Amit has recommended. Extract unqiue values into a new bridge table, then connect the bridge table to the other data tables instead of building relationships between those tables directly. You can achieve one-to-many or one-to-one relationship between the bridge table and the other tables. 

Another method is to concatenate multiple columns to form a new column, then establish relationships with the new columns. This method is usually used when a single column is not able to act as a "key" column for building the relationship, so we need to use multiple columns for the purpose. 

In addition, sometimes we can remain the many-to-many relationships but change their cross-filter direction from Both to Single(using one table filters the other) according to your need. 

Here are some guidance documentations for your reference:

Many-to-many relationship guidance - Power BI | Microsoft Learn

Different options to model many-to-many relationships in Power BI and Tabular - SQLBI

Many-to-many relationships in Power BI Desktop - Power BI | Microsoft Learn

Best Regards,
Jing
If this post helps, please Accept it as Solution to help other members find it. Appreciate your Kudos!

[amitchandak · Accepted solution]

@DryMouse555 , Create common dimensions of bridge tables

Power BI- DAX: When I asked you to create common tables: https://youtu.be/a2CrqCA9geM
https://medium.com/@amitchandak/power-bi-when-i-asked-you-to-create-common-tables-a-quick-dax-soluti...