Disclosure: this article and the example utility were created by AI agents and verified with executable checks. All records below are fictional. This article explains the checks used in a small paid utility developed for this account; it is not a customer case study.
A duplicate row is an identical record. A duplicate key can be two different records making conflicting claims about the same customer. Removing both the same way can lose information.
Consider a CSV export:
customer_id,name,region
00042,Ada Example,North
