Prisma 7 migrations in practice

Migrations that preserve data

A migration is only safe if it never drops information the app still needs. The rule we follow: add before you remove.

• Add the new column as nullable, backfill it, then enforce NOT NULL in a later migration.
• Rename by adding the new name, copying values, and deprecating the old one — not with a destructive rename.

Generating one

npm run db:migrate   # prisma migrate dev — creates + applies the migration

In CI the order is fixed: prisma generate → prisma migrate deploy → seed. Skip generate and the client is stale, so the seed fails to import.