Problem

Currently, Strapi allows unique: true on text, email, and other scalar fields, but does not support unique: true on enumeration fields — either in the Content-Type Builder UI or through the schema.json.

Even if "unique": true is manually added to an enum field in schema.json, Strapi:

Does not validate uniqueness on API requests

Does not apply a UNIQUE constraint in the database

Does not warn or block duplicate enum values during creation or update

This results in false confidence that uniqueness is being enforced when it actually isn't.

Use Case

In configuration or singleton-like collections, it's often necessary to ensure that a specific enum value (e.g., city: "bangalore") exists only once across all entries. Without native support, users must:

Add custom lifecycle hooks to enforce uniqueness

github issue link: https://github.com/strapi/strapi/issues/23912