@llodev/django-schema-design

Design production-ready Django database schemas — primary-key strategy, indexes, constraints, and safe migrations — with the non-obvious trade-offs an expert learned the hard way, not basic ORM syntax.

Part of the @llodev/django-* family.

What you get:

• PK strategy that names the real axis — not "unique vs not" (all are unique) but random placement (UUIDv4) vs sequential placement (UUIDv7 / incremental), and why v4 as a hot-table PK fragments the index while v7 keeps insert locality.
• A domain-interrogation frame — identity, cardinality/ownership, lifecycle, access paths — to settle before any field exists.
• An indexes & constraints expert layer — composite column ordering, covering (include) and partial indexes, Unique/Check/Exclusion constraints, B-tree/GIN/GiST/BRIN selection, and when to denormalize instead of adding another index.
• Migration safety — batched backfills, concurrent index creation on live tables, reversibility, and the staged PK-swap procedure.
• A NEVER list with the reasons experience teaches (FloatField money drift, sequential PK → IDOR, v4-on-hot-tables, in-place PK swaps, implicit on_delete).

Install

# npm (with skillpm or Claude Code marketplace)
npm i @llodev/django-schema-design

# Vercel CLI
npx skills add llodev/skills/skills/django-schema-design

No MCP, no config, no init — it's a pure knowledge skill. Once installed it activates on prompts like the ones below.

Use

| Prompt example | What the agent does | | ------------------------------------------------------- | --------------------------------------------------------------------------- | | "design Django models for invoices and line items" | Runs the domain frame + PK decision flow, emits models.py with rationale | | "should this event table use UUID or auto increment?" | Applies the exposure + insert-locality axes → UUIDv7 with the reasoning | | "migration to switch users to a UUID PK" | Staged, reversible add→backfill→repoint→swap procedure | | "review this schema" | Checks PK choice, on_delete, constraints, index ordering against the list |

Contents

| File | Content | | ---------------------------------------- | ----------------------------------------------------------------------- | | SKILL.md | Domain frame, PK decision flow, NEVER list, and verification checklist. | | references/pk-strategy.md | Incremental vs UUIDv4 vs UUIDv7, storage/collation, and PK migration. | | references/indexing-and-constraints.md | Composite/covering/partial indexes, constraints, index types, EXPLAIN. |

License

MIT — see LICENSE.