---
title: RDBMS Playground
description: A terminal playground for learning relational databases — tables, keys, relationships, indexes, queries, and query plans, hands-on.
template: splash
# Title-only hero: this keeps Starlight's splash from emitting a second,
# page-title
in a content panel (which can't be styled per-page). The hero
# lives inside `.hero`, so it can be visually hidden (kept for SEO/a11y)
# while the Wordmark + tagline + buttons below it carry the visible hero — see
# `.hero h1` in global.css. tagline/actions are rendered in the body so they sit
# *below* the wordmark, where the old title used to be.
hero:
title: RDBMS Playground
---
import { Card, CardGrid, LinkCard, LinkButton } from '@astrojs/starlight/components';
import Demo from '../../components/Demo.astro';
import Wordmark from '../../components/Wordmark.astro';
Learn relational databases by doing — in your terminal.
Get started
Browse the reference
RDBMS Playground is a cross-platform terminal app that gives you a safe
sandbox for exploring relational database concepts: tables, columns,
primary and foreign keys, relationships, indexes, queries, and query
plans. It is built for learning — from your first table to writing raw
SQL.
Start in **simple mode** — a friendly, keyword-based command language —
and switch to **advanced mode** for standard SQL whenever you are ready.
Modes →
Run a simple-mode command in advanced mode and the playground shows you
the equivalent SQL, so the bridge from concepts to SQL is always visible.
Seeing the SQL →
Every change can be undone, your work is saved as you go, and you can
rebuild the whole database from plain, readable files.
Undo and history →
Ask the playground to explain any query and it renders the database's
plan as an annotated tree — so indexes and scans stop being a mystery.
Query plans →
The input field completes commands with Tab, highlights
syntax, flags mistakes before you run them, and hints what comes next.
The assistive editor →
## Start here