Why Does HDL Create Duplicate Employees That Already Exist in Oracle HCM?

Hi everyone,

I’m using HDL to create users in Oracle HCM and reconciling the results using a report. However, I've noticed that some users are being duplicated — they already exist in the system, yet HDL creates them again as new records.

This raises a few questions:

1 -Does HDL not validate if an employee or user already exists, based on key fields like email, person number, or user name?

2- If a person already exists in Oracle, what validation is in place (if any) to prevent HDL from creating a duplicate?

3- What are the best practices to avoid duplication when loading data via HDL?