Multiple Prisma Clients, One App

There are times where you need to connect to multiple databases within a single backend server. I've found this is a lightly documented subject on the official Prisma docs, and wanted to make a quick guide for others.

I have been working on a GraphQL server that combines multiple internal datasets from our company, so it's crucial that I can easily query all of these different Postgres databases.

Initial Setup

In the top level of your app (where the package.json is located) install prisma like normal:

yarn add prisma @prisma/client

Next, create a new folder for every database you need to access. For example purposes we will make a folder called db1 and db2

In each folder, run the following:

npx prisma init

Next, open the prisma/schema.prisma file, and make one change:

generator client {
  provider = "prisma-client-js"
  output   = "../../src/generated/db1"
}

We are telling it to output the client into our src folder at the root of the project, inside of a generated folder. You should add this f…