# 1. Modify schema.prisma
model User {
  id    Int    @id @default(autoincrement())
  email String @unique
  name  String
}

# 2. Create migration
npx prisma migrate dev --name add_user_model

# Creates migration file and applies it

# Deploy migrations (non-interactive)
npx prisma migrate deploy

# CI/CD pipeline

# ❌ Never use migrate dev in production
npx prisma migrate dev

// ✅ Adding optional field
model User {
  id       Int     @id
  email    String  @unique
  bio      String? // Existing rows get NULL
}

// ✅ Adding field with default
model User {
  id        Int      @id
  email     String   @unique
  role      String   @default("USER")
  createdAt DateTime @default(now())
}

// Step 1: Add new field mapping to same column
model User {
  id       Int    @id
  name     String
  fullName String @map("name")
}

// Step 2: Update app code to use fullName
// Step 3: Remove old field
model User {
  id       Int    @id
  fullName String @map("name")
}

// ❌ Direct rename (data loss)
model User {
  id       Int    @id
  fullName String // Was "name", data lost!
}

// Step 1: Add default
model User {
  id    Int     @id
  name  String? @default("")
}

npx prisma migrate dev --name add_default_name

// Step 2: Backfill NULL values
await prisma.$executeRaw`UPDATE "User" SET name = '' WHERE name IS NULL`

// Step 3: Make required
model User {
  id    Int    @id
  name  String @default("")
}

// schema.prisma
model User {
  id        Int      @id @default(autoincrement())
  email     String   @unique
  name      String
  createdAt DateTime @default(now())
  posts     Post[]
}

model Post {
  id        Int      @id @default(autoincrement())
  title     String
  content   String
  published Boolean  @default(false)
  authorId  Int
  author    User     @relation(fields: [authorId], references: [id])
  createdAt DateTime @default(now())
}

# Create migration
npx prisma migrate dev --name add_post_model

# Applies migration and generates Prisma Client

// Backfill default values before making field required
import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function backfillUserNames() {
  // Update all NULL names to empty string
  await prisma.$executeRaw`
    UPDATE "User"
    SET name = COALESCE(name, '')
    WHERE name IS NULL
  `;

  console.log('Backfill complete');
}

backfillUserNames()
  .catch(console.error)
  .finally(() => prisma.$disconnect());

# 1. Backup
pg_dump production_db > backup_$(date +%Y%m%d).sql

# 2. Deploy code (if backward compatible)
git push production main

# 3. Run migrations
npx prisma migrate deploy

# 4. Verify
npx prisma migrate status