SQL Playground
1 language| Type | Interactive demo |
|---|---|
| Origin | DTU Databases course |
| Developer | David |
| Written in | SQL (MariaDB), SQLite, sql.js (WASM), TypeScript |
| Tests | Every query preset fixture-tested against Python sqlite3 |
| Built with | DTU Databases weekly answer sheets and schemas, translated to SQLite |
| Hosted on | David-Internet/demos/sql |
| Website | https://david-internet.vercel.app/demos/sql |
SQL Playground is an interactive demonstration of five databases from a DTU Databases course, running entirely in the browser.[1]Schemas were translated from MariaDB to SQLite at build time. sql.js runs SQLite compiled to WebAssembly, so there is no server.
A schema browser draws tables and foreign keys beside hand-drawn ER designs. A query runner fires the weekly answer queries, or a visitor's own SQL, and highlights involved tables and touched rows.
Overview
The five course databases are the Silberschatz University schema, a Family warm-up, a Cinema exam set, and the week 12 and 13 Takeaway and Bus Service sets. A reconstructed bike-shop schema supports the modification panel.
Query runner
Forty-four presets cover joins, left joins, group-by-having, correlated subqueries, and the cinema exam's nine answers. MariaDB-only features are adapted and disclosed per preset. A modification panel replays INSERT, UPDATE, and DELETE with undo, a foreign-key toggle, and a trigger rewritten from SIGNAL to RAISE.
Development
Every query preset fixture-tested against Python sqlite3. The engine is client-side so a static export of David's Internet can host the lab.
See also
References
- ^
content/sql/README.md, David's Internet.
- Interactive demos
- Databases
- 2026 establishments