M:M relationship instead of 1:M

[Dunner2020]

Hi there,

I have two tables: The account table and LATs. The account table contains all information about the individuals. This table is like a master table whereas LATs contain specific information of individuals (it's like a subset of Account table). I am trying to draw a relationship between two tables. When I tragged the Registration Number column of the Account table to final Individual ID of LATs table, the windows give me option to draw M:M relationship instead of 1:M.

I checked manually and all record of LATS table is present in Account Table. I am not sure why is it asking to draw M:M relationship. Any help would be really appreciated to solve the issue:

Data File here

[amitchandak · Accepted solution]

@Dunner2020 , there is some problem is uploaded with file, It is opening like zip, not like pbix.

The problem is usaually when you have More than value or blank/null value on the one side ot the table