Guide to using Prisma with PlanetScale

content/300-guides/050-database/500-planetscale-guide.mdx

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+---
+title: 'Prisma with PlanetScale'
+metaTitle: 'Prisma with PlanetScale'
+metaDescription: 'Guide on using Prisma with PlanetScale'
+tocDepth: 2
+toc: true
+---
+
+<TopBlock>
+
+Prisma and PlanetScale together provide a development arena that optimizes rapid, type-safe development of data access applications, using Prisma's ORM and PlanetScale's highly scalable MySQL-based platform.
+
+</TopBlock>
+
+## About using Prisma with PlanetScale
+
+This document discusses the concepts behind using Prisma and PlanetScale, explains some important concepts and considerations on the commonalities and differences between PlanetScale and other dtabase providers, and leads you through the process for configuring your application to implement PlanetScale.
+
+Two main benefits of using Prisma with PlanetScale are:
+
+- enterprise scalability
+
+  - !!use Jan's content
+
+- support non-blocking schema changes
+  - !!use Jan's content
+
+Watch our video on [Best Practices when using Prisma with PlanetScale](https://www.youtube.com/watch?v=iaHt5_hg44c).
+
+## Commonalities with other database providers
+
+Many aspects of using Prisma with PlanetScale are just like using Prisma with any other database.
+
+- You still model your database with Prisma Schema Language
+- You can use `mysql` as the provider that you define in your schema, plus the [connection string PlanetScale provides you](https://docs.planetscale.com/concepts/connection-strings)
+- Use Introspection for existing projects if you already have a database schema in PlanetScale
+- Use `db pull` to migrate your database schema
+- Use Prisma Client in your application to talk to the database server at PlanetScale
+
+## Differences to consider
+
+There are important considerations to be aware of when working with PlanetScale, such as how to handle referential integregrity, because PlanetScale does not enforce foreign key constriants.
+
+Referential integrity is managed ....
+
+- Prisma emulates “missing” referential integrity on PlanetScale in Prisma Client
+  .....
+
+- branches + deploy requests
+
+  - [https://docs.planetscale.com/concepts/branching](https://docs.planetscale.com/concepts/branching)
+
+- **Migrations** with Prisma when using multiple branches:
+
+  - ⇒ Recommend `prisma db push` instead of `prisma migrate`
+    - TODO Reasoning
+
+## Additional considerations
+
+- Defining indices on foreign keys (@@index)
+- using db push (migrate has no value)
+- Use expand and contract for “breaking changes” (renames aren’t supported anyways)
+
+  > **No schema changes on your production database**
+
+  - ⇒ _have_ to use branches and deploy requests when working with production branch
+
+  > **No data copying between branches**
+
+  - Migrate needs migration table to work
+  - ⇒ enable migration table copy in settings on PS
+
+  -- defining an index on an implicit many-to-many relation... creating indices for relation scalars with referentialIntegrity set to Prisma (and the proposal: https://github.com/prisma/prisma/issues/10611)
+
+## How to implement Planetscale
+
+!!sentence about how you can use it in either PDP or with ORM
+
+### PlanetScale and the ORM....
+
+The fastest way to start using PlanetScale with the Prisma ORM is to refer to our Getting Start documentation:
+
+- [Start from scratch](https://www.prisma.io/docs/getting-started/setup-prisma/start-from-scratch/relational-databases-typescript-planetscale)
+
+- [Add to existing project](https://www.prisma.io/docs/getting-started/setup-prisma/add-to-existing-project/relational-databases-typescript-planetscale)
+
+### PlanetScale on the Prisma Data Platform
+
+TODO Description of the integration and its benefits... eventually we can link to separate Platform docs.