Prisma in practice

📘What it really is

• Set up:

npm install prisma --save-dev
npm install @prisma/client
npx prisma init

• Describe tables in prisma/schema.prisma:

model Customer {
  id        String   @id @default(uuid()) @db.Uuid
  name      String
  email     String?  @unique
  phone     String
  city      String
  createdAt DateTime @default(now()) @map("created_at") @db.Timestamptz
  orders    Order[]

  @@map("customers")
}

model Order {
  id          String   @id @default(uuid()) @db.Uuid
  customer    Customer @relation(fields: [customerId], references: [id], onDelete: Restrict)
  customerId  String   @map("customer_id") @db.Uuid
  totalPaise  Int      @map("total_paise")
  placedAt    DateTime @map("placed_at") @db.Timestamptz

  @@index([customerId])
  @@map("orders")
}

@map keeps snake_case names in the database and camelCase in code.

• npx prisma migrate dev --name init creates and runs a migration (SQL you can read in prisma/migrations/). npx prisma migrate deploy applies migrations in production.

• Queries:

await prisma.customer.create({ data: { name, phone, city } });
await prisma.customer.findMany({ where: { city: "Patna" }, orderBy: { name: "asc" }, take: 25 });
await prisma.order.findMany({ include: { customer: true } });     // join, not N+1
await prisma.$transaction(async (tx) => { /* several operations */ });

• For SQL Prisma can't express well, use prisma.$queryRaw with its tagged template, which still parameterises: prisma.$queryRaw`SELECT ... WHERE city = ${city}`. Never use the Unsafe variants with user input.

• npx prisma studio opens a browser view of your data.

• If you already have a database, npx prisma db pull creates the schema from it.