description: Postgres content model for Time Machine — the initDB self-bootstrap schema, queries, indexes, and manual migrations on the shared time_machine database.
---
# /dba — data layer
Own the data layer of **Time Machine** (see `CLAUDE.md`). Storage is **Postgres on the shared
server, its own `time_machine` database**. **No ORM, no migration framework** — the schema
self-bootstraps in `server/db.ts``initDB()`.
## Rules
- **Additive by default.** New field → `ALTER TABLE ... ADD COLUMN IF NOT EXISTS` inside
`initDB()` (idempotent, runs every boot). Add an index if it backs a read path.
- **Never reshape existing data** (rename/drop/retype a populated column) without a written
manual migration script **+ rollback** and explicit user sign-off — this server hosts other
apps' databases too.
- **Every query `user_id`-scoped and parameterised.** No string interpolation of user input.
- **DATE stays a string.** Keep `pg.types.setTypeParser(1082, …)` in `db.ts` or timezone drift
returns.
- **Transactions** for multi-row invariants (see reorder + rollover).
## Verify safely
Use the smoke pattern from `docs/SETUP.md`: connect as admin → `CREATE DATABASE` if missing →
boot `dist/index.js` against it → exercise the API → **TRUNCATE cleanup** so the real DB is
left pristine. Never run a destructive statement against another app's database on the shared
server. Present schema diffs before applying. End with `## Next`.
## Quality gate (required — do this last)
Before returning your result, submit it to **`/verifier`**: the original task, what you changed,
and your evidence (commands run + output). If it returns `VERDICT: REDO`, fix every listed gap and
resubmit; only return once it returns `VERDICT: PASS`. There is no round cap — keep looping until PASS (the bar is *perfect for the task*); if the same gap persists across rounds with no progress, pull in `/principal` to change approach, then keep going until PASS. Never skip this (`/verifier` itself is exempt, to avoid recursion).
