Database Migrations

Learn how to run database migrations safely in production.

Goal

By the end of this recipe, you'll know how to create and apply database migrations in production.

Prerequisites

• A working Plainform installation
• Prisma configured
• Production database access

Steps

npx prisma migrate dev --name add_new_field

git add prisma/migrations/
git commit -m "feat: add new database field"
git push origin main

{
  "scripts": {
    "postinstall": "prisma generate && prisma migrate deploy"
  }
}

vercel env pull .env.production
npx prisma migrate deploy

npx prisma studio

Migration Best Practices

Before Running Migrations

• Backup your database before major schema changes
• Test locally with production-like data
• Review SQL in migration files for correctness

Safe Migration Patterns

Adding columns:

model User {
  id    String @id
  email String
  name  String? // Make new fields optional initially
}

Renaming columns:

1. Add new column
2. Copy data from old to new
3. Remove old column (in separate migration)

Dropping columns:

1. Remove from application code first
2. Deploy application
3. Drop column in separate migration

Common Issues

Migration Fails in Production

• Check database connection string
• Verify database user has migration permissions
• Review migration SQL for syntax errors

Schema Out of Sync

Reset and reapply migrations:

npx prisma migrate reset
npx prisma migrate deploy

Migration Conflicts

If multiple developers create migrations:

npx prisma migrate resolve --applied <migration_name>

Rollback Strategy

To rollback a migration:

1. Revert the migration commit in Git
2. Create a new migration that undoes changes
3. Deploy the rollback migration

Next Steps

• Deploy Vercel - Deploy your application

Related Documentation

• Prisma Migrations - Complete migration guide
• Prisma Deploy - Production migration docs