Instantiating Prisma Client
1. Creating PrismaClient Instance
import { PrismaClient } from "@prisma/client" ; export const prisma = new PrismaClient ();
Note Detail Connection Lazy: opens on first query Pooling Internal pool (one process)
2. Configuring Client Options
Option Purpose logLogging config datasourcesOverride URL per environment errorFormat"pretty" | "colorless" | "minimal"transactionOptionsDefault timeout/isolation
3. Using Singleton Pattern
Example: Next.js / Node singleton
import { PrismaClient } from "@prisma/client" ; const globalForPrisma = globalThis as unknown as { prisma ?: PrismaClient }; export const prisma = globalForPrisma.prisma ?? new PrismaClient (); if (process.env. NODE_ENV !== "production" ) globalForPrisma.prisma = prisma;
Why Detail Avoid leaks Hot-reload creates multiple clients otherwise Connections Re-use pool across modules
4. Managing Development Hot Reload
Framework Approach Next.js Singleton via globalThis tsx / nodemon Same singleton works Bun Use --hot + singleton
Mode Output prettyColored, multi-line (dev default) colorlessMulti-line plain minimalOne-line (prod)
6. Configuring Data Sources
const prisma = new PrismaClient ({ datasources: { db: { url: process.env. READ_REPLICA_URL ! } } });
Use Detail Override URL Different DB per tenant/env Per-request Instantiate scoped client (costly)
7. Using Multiple Client Instances
Pattern Use Case Per database Microservices reading two DBs Per tenant Multi-tenant URL switching Read/write split One client per replica
8. Implementing Lazy Loading
Aspect Detail Default Connection opens on first query Force await prisma.$connect() in warm path
9. Handling Client Initialization Errors
Error Cause PrismaClientInitializationErrorBad URL, binary not found P1001Can't reach DB P1002Connection timed out
10. Using Global Prisma Instance
// lib/prisma.ts import { PrismaClient } from "@prisma/client" ; export const prisma = (globalThis as any ).prisma ?? new PrismaClient (); (globalThis as any ).prisma = prisma;
Best Practice Detail Export from single module Re-import everywhere Disconnect Gracefully on SIGTERM in servers