---
title: 'Database polyfills'
metaTitle: 'Database polyfills (Concepts)'
metaDescription: 'Prisma Client provides features that are not achievable with relational databases. These features are referred to as "polyfills" and explained on this page.'
hide_table_of_contents: true
---

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Prisma Client provides features that are typically either not achievable with particular databases or require extensions. These features are referred to as _polyfills_. For all databases, this includes:

- Initializing [ID](/orm/prisma-schema/data-model/models#defining-an-id-field) values with `cuid` and `uuid` values
- Using [`@updatedAt`](/orm/prisma-schema/data-model/models#defining-attributes) to store the time when a record was last updated

For relational databases, this includes:

- [Implicit many-to-many relations](/orm/prisma-schema/data-model/relations/many-to-many-relations#implicit-many-to-many-relations)

For MongoDB, this includes:

- [Relations in general](/orm/prisma-schema/data-model/relations) - foreign key relations between documents are not enforced in MongoDB

</TopBlock>
