Prisma Migrations Without Surprising Production

Expand-contract

Never drop a column in the same deploy that stops reading it. The safe sequence:

1. Add new column (nullable)
2. Dual-write in application code
3. Backfill data
4. Switch reads to new column
5. Remove old column in a later migration

Prisma-specific tips

• Use prisma migrate deploy in CI, not db push, for production.
• Review generated SQL for locking behavior on large tables.
• Keep migrations small — one logical change per migration.

When ORM isn't enough

For index creation on huge tables, use CREATE INDEX CONCURRENTLY via $executeRaw in a dedicated migration step.