# Migration Rules (V2)

## Safety rules
- Only ONE migration per file.
- Phase 1 must be additive (no drops/renames).
- Never rename tables/columns in Phase 1.
- For type fixes (money/coords): add new columns first, backfill later.

## Data rules
- Money must not be stored as varchar long-term.
- Coordinates must be DECIMAL(10,7) or similar.
- Status changes must be logged (history tables).

## Rollback rules
- Avoid destructive downs when data could violate old constraints (enums).
- Prefer forward-only changes + explicit rollback procedure.