---
description: Coredata SQL migration naming and conventions
globs: pkg/coredata/migrations/*.sql
alwaysApply: false
---

# Coredata migrations

See full guides: `contrib/claude/coredata.md` (Migrations) and
`contrib/claude/license.md` (SQL header).

## Naming — never invent or infer the timestamp

Migration files use UTC timestamp naming `YYYYMMDDTHHMMSSZ.sql`. The
timestamp is the **real current time**, obtained by running the command —
do NOT hand-write a round number (e.g. `...T100000Z`) and do NOT infer the
next name from existing files.

```bash
# Run this and use its exact output as the filename:
date -u +"%Y%m%dT%H%M%SZ.sql"
```

## License header

Every `.sql` file starts with the MIT header (use the current year). Copy
the exact block from `contrib/claude/license.md` (SQL section).

## Content rules

- One logical change per file.
- No indexes by default — add one only when justified by observed
  production latency. Constraint-enforcing indexes (e.g. unique) are exempt.
- Avoid `DEFAULT` clauses. When adding a non-nullable column to an existing
  table, set a `DEFAULT` to backfill existing rows, then `DROP DEFAULT` in
  the same migration so inserts must supply the value explicitly.