community.
I am using AWS Cognito as a user management system for my project.
My project is using RDS of AWS as a database.
As I am using AWS Cognito, I don’t have user table in my relational database.
But there are several tables that is related to user table(has user_id as a foreign key).
So in this case that I don’t have user table(but AWS Cognito) while I need to make relation some other tables with users, how to deal with this properly?
What is the best solution?

I tried to make user table in database, but I don’t think this is advisable because it means data duplication.
So same data(user) will be stored in database and Cognito.
This is not good idea.
I am expecting that there is a method to join Cognito table and RDS tables directly just like we do in MySQL.