# Database Design & Modeling

> Selected work demonstrating this service.

- [Built the payments and entitlements layer — Stripe alongside Apple and Google in‑app purchase — gating the directory, search and export through an 11‑table access model checked on the server.](https://advisory.engineer.company/portfolio/built-the-payments-and-entitlements-layer-96/)
- [Built the loyalty and reputation system — 67 functions over a 31‑table ledger, with leagues, badges and a redemption shop — taking a row lock on the balance to close the double‑spend window.](https://advisory.engineer.company/portfolio/built-the-loyalty-and-reputation-system-105/)
- [Built the hiring marketplace and the seafarer career workspace — 151 stored functions across 48 tables — covering vacancies, applications, certificates, rank progression and verified sea time.](https://advisory.engineer.company/portfolio/built-the-hiring-marketplace-and-career-workspace-107/)

<https://advisory.engineer.company/services/database-design/>