Add Open Connections To Multiple Databases as a Prisma TIL

prisma/open-connections-to-multiple-databases.md

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+# Open Connections To Multiple Databases
+
+A standard database connection with Prisma is determined by a `DATABASE_URL`
+env var set in the `.env` file of your project. Typically, the Prisma client
+connecting to that URL will be configured in a separate file and imported
+wherever it is used.
+
+```javascript
+import {prisma} from './utils/prisma'
+```
+
+What if you want to connect to a second, alternate database?
+
+You can create a new Prisma client with the data source configured to be a
+different connection URL.
+
+```javascript
+import {prisma as primaryPrismaClient} from '@skillrecordings/database'
+import {PrismaClient} from '@prisma/client'
+
+const secondaryDatabaseUrl = 'mysql://root@localhost:3399/my-database'
+
+const secondaryPrismaClient = new PrismaClient({
+  datasources: {
+    db: {
+      url: secondaryDatabaseUrl
+    }
+  },
+})
+```
+
+And with that, you can execute queries against both databases.
+
+```javascript
+const primaryUserCount = await primaryPrismaClient.user.count()
+const secondaryUserCount = await secondaryPrismaClient.user.count()
+```
+
+[source](https://www.prisma.io/docs/reference/api-reference/prisma-client-reference#programmatically-override-a-datasource-url)