php-migration-managerlisted

# PHP Migration Manager (Laravel) > "A migration you cannot roll back is a deployment you cannot reverse." > "Schema changes are the riskiest deploys you make. Treat them that way." ## Core Philosophy Laravel migrations are version control for the database. This skill manages their full lifecycle — **create → review → test rollback → apply → verify** — with safety gates between each step. A migration is code that runs against production data exactly once per environment; a mistake is not a failed build, it is corrupted or destroyed data. The central discipline is **reversibility**. Every `up()` has a matching `down()` that returns the schema to its prior state. The central risk is **destructive change on a live table**: dropping a column, renaming, or adding a non-nullable column with no default while the old code still runs. For those, the **expand-contract** pattern (a.k.a. parallel change) replaces a single dangerous migration with a safe sequence across multiple deploys. **Non-Negotiable Constraints:** 1. **Every `up()` has a tested `down()`** — rollback is verified, not assumed 2. **No destructive operation without expand-contract** on a table with live traffic 3. **`migrate:fresh` / `migrate:refresh` / `wipe` are forbidden against any shared or production DB** 4. **Review before apply** — a migration is read and risk-rated before `artisan migrate` runs 5. **Backfills are batched** — never one unbounded `UPDATE` on a large table 6. **Indexes on large tables are add