Prisma migrations — managing database schema changes safely

Managing Schema Changes with Prisma Migrate

Database schemas change over time. Prisma Migrate tracks every schema change as a versioned SQL migration file, giving you a reproducible history of how the database evolved.

Development Workflow

# Make schema changes in schema.prisma, then:
npx prisma migrate dev --name add_post_published_field
# This: generates a SQL migration file
#       applies it to your dev database
#       regenerates the Prisma Client

-- Example generated migration file
ALTER TABLE "Post" ADD COLUMN "published" BOOLEAN NOT NULL DEFAULT false;

Production Workflow

# In CI/CD pipeline or deployment script:
npx prisma migrate deploy
# Applies all pending migration files (never generates new ones)
# Safe to run in production — only applies, does not modify schema.prisma

Critical Rules

Never edit migration files after they are committed. Never use prisma migrate dev in production — use migrate deploy. Use prisma db push only for prototyping (it doesn't create migration files and will cause drift). Before adding a NOT NULL column to a production table with existing rows, always provide a default value or run a data migration first to avoid constraint failures.