Are you going to identify the same customer? We'll create a key based on which data will determine whether the customer is the same.

To identify the same customer across multiple sources, we create a composite key that combines the most reliable identifiers. A common approach is to hash a concatenation of email, phone number, and normalized name. If any of these fields are missing, we use the next best combination. For example, key = SHA256(email + phone + name). This deterministic key allows us to join datasets and flag duplicates. We also maintain a lookup table that maps each raw identifier to the canonical customer ID, enabling incremental updates. In cases where identifiers are inconsistent, we supplement with fuzzy matching on name and address, assigning a confidence score. Records with a score above a threshold are merged; otherwise, they remain separate. This hybrid deterministic‑fuzzy strategy balances accuracy and performance.