# Customer records were stored without a unique identifier, and now there are duplicates

Canonical URL: <https://datadriven.io/problems/customer-records-were-stored-without-a-unique-identifier-an-edb5c93d>

Domain: Data Modeling · Difficulty: medium

## Problem

Customer records were stored without a unique identifier, and now there are duplicates. Design a table structure that guarantees every row is unique.

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