Prisma Patterns

Prisma Patterns (ForemanOS)

Prisma 6.7 with PostgreSQL (Neon serverless). 112 models, @prisma/client generated to node_modules/.prisma/client.

When to Use This Skill

• Writing or modifying Prisma queries
• Adding or changing schema models
• Working with transactions
• Fixing database connection issues
• Writing database helper utilities

Core Patterns

Prisma Client Singleton (lib/db.ts)

The Prisma client uses a global singleton with lazy construction. Always import from @/lib/db:

import { prisma } from '@/lib/db';

Key details from the actual implementation:

• Uses globalThis to preserve a single instance across hot reloads in development
• Lazy construction: skips PrismaClient creation when DATABASE_URL is missing (happens during Trigger.dev Docker build indexing)
• Falls back to a Proxy that throws on any property access when DATABASE_URL is not configured
• Production logging: ['error'] only. Development: ['error', 'warn']
• Graceful shutdown via process.on('beforeExit'|'SIGINT'|'SIGTERM')

Schema Conventions

From prisma/schema.prisma:

generator client {
  provider      = "prisma-client-js"
  output        = "../node_modules/.prisma/client"
  binaryTargets = ["native", "debian-openssl-1.1.x"]
}

datasource db {
  provider  = "postgresql"
  url       = env("DATABASE_URL")
  directUrl = env("DIRECT_DATABASE_URL")
}

Model conventions observed across 112 models:

• IDs: @id @default(cuid()) — always CUID strings
• Timestamps: createdAt DateTime @default(now()) and updatedAt DateTime @updatedAt
• Soft delete: deletedAt DateTime? (used on DailyReport)
• Indexes: Always add @@index for foreign keys and frequently queried fields
• Compound indexes: @@index([budgetId, isActive]) for filtered queries
• Unique constraints: @@unique([provider, providerAccountId]) for compound uniqueness
• Cascade deletes: onDelete: Cascade for child records, onDelete: SetNull for optional refs
• Enums: PascalCase names, SCREAMING_SNAKE values (e.g., ChangeOrderStatus, PENDING)

Transaction Patterns

Two transaction styles used in the codebase:

Batch transaction (for independent operations):

// From src/trigger/process-document.ts — multiple updates that must succeed together
await prisma.$transaction([
  prisma.document.update({
    where: { id: documentId },
    data: { queueStatus: 'processing' },
  }),
  prisma.processingQueue.update({
    where: { id: queueEntry.id },
    data: {
      status: ProcessingQueueStatus.processing,
      updatedAt: new Date(),
    },
  }),
]);

Interactive transaction (when operations depend on each other):

// From lib/document-processor.ts
await prisma.$transaction(async (tx) => {
  // Use tx instead of prisma inside the callback
  const doc = await tx.document.findUnique({ where: { id } });
  await tx.documentChunk.create({ data: { ... } });
});

// From app/api/projects/invitations/[id]/accept/route.ts
await prisma.$transaction(async (tx: any) => {
  // Accept invitation and create project member atomically
});

Query Patterns

Case-insensitive search (used in auth):

const user = await prisma.user.findFirst({
  where: {
    OR: [
      { username: { equals: identifier, mode: 'insensitive' } },
      { email: { equals: identifier, mode: 'insensitive' } },
    ],
  },
  include: {
    Project_User_assignedProjectIdToProject: true,
  },
});

Selective fields with select:

const project = await prisma.project.findUnique({
  where: { id: projectId },
  select: { ownerId: true },
});

Increment pattern:

await prisma.document.update({
  where: { id: documentId },
  data: { processingCost: { increment: batchCost } },
});

Database Retry Helper (lib/db-helpers.ts)

For operations that may fail due to connection issues:

import { withRetry } from '@/lib/db-helpers';

const result = await withRetry(
  () => prisma.document.findMany({ where: { projectId } }),
  'fetch project documents'
);

Retryable Prisma error codes: P2024 (connection pool timeout), P1001 (unreachable), P1002 (timeout), P1008 (operations timeout), P1017 (connection closed).

Prisma Error Classification

From the Trigger.dev task (src/trigger/process-document.ts):

import { Prisma } from '@prisma/client';

if (error instanceof Prisma.PrismaClientKnownRequestError) {
  // P2025 = record not found — NOT retryable
  // P2003 = foreign key constraint — NOT retryable
  // P2002 = unique constraint violation — NOT retryable
  // P2024, P1001, P1002 = connection errors — retryable
}

Anti-Patterns

• Never import PrismaClient directly — always use import { prisma } from '@/lib/db'
• Never use prisma.$connect() in API routes — the singleton handles connections
• Never create new PrismaClient instances in request handlers
• Never use findUnique with non-unique fields — use findFirst instead
• Never omit @@index on foreign key fields — all foreign keys must be indexed
• Never use autoincrement() for IDs — always use cuid()

Quick Reference