Natural Key
A natural key is a type of database key that uses existing, meaningful data attributes from the real world to uniquely identify records in a table, such as a social security number for a person or an email address for a user. It contrasts with surrogate keys, which are artificially generated identifiers like auto-incrementing integers or UUIDs. Natural keys are derived from the business domain and have inherent meaning beyond just database identification.
Developers should use natural keys when the data naturally includes a unique, stable, and immutable attribute that can serve as a reliable identifier, such as in systems where business rules enforce uniqueness (e.g., product codes in inventory management). They are beneficial for simplifying database design, improving data integrity through real-world constraints, and reducing the need for additional columns, but they require careful consideration to avoid issues like changes in key values over time.