How do I deal with duplicate values in Column which supposed to be unique and establish relationship

[anilkumarpoda]

Hi, in a health policy database there are 3 tables

Scheme - With scheme details along with Company_Code, start date.

Membership - Employe Membership details with Ref_Num, Schem_Code, start date.

Usage - Member ship utilization details with creation date.

Scheme start date can be different from Membership start date, becuase employee can join the scheme any date after scheme start date. Note: Company_Code = Scheme_Code

Ref_Num in Membership has duplicate values, how do I deal with this duplicate values and establish relation between Membership and Usage?

Download dataset using below link:

Dataset 

[anilkumarpoda · Accepted solution]

There is a problem with dataset itself. It's not even possible to create an unique column even by combining two columns and establishing relationship with other tables. Deleted duplicates manually as there are few duplicates.

[Padycosmos]

Hope this video helps:

https://drive.google.com/file/d/1na2-YBiK2AGJVbmC85IQiue3E03uVikv/view?usp=sharing