I have this IdentityServer which handles authentication and authorization. It saves users, roles, claims, etc in its own database.
Then, I have a web app that needs to protect some resources to specific roles. This is, of course, handled by the IdentityServer.
Now, the question is, I need to associate some entities in my webapp to a specific user. Before moving authentication to a separate IdentityServer we simply had a 1-1 SQL relationship in our database. But now, since users lives in a different database, we can't simply do that.
So, what's the proper approach to handle this relationship between entities that lives in different databases?