Two ways to work
Start in simple mode — a friendly, keyword-based command language — and switch to advanced mode for standard SQL whenever you are ready.
Modes →RDBMS Playground
RELational DataBase Management System PLAYground
Learn relational databases by doing — in your terminal.
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.
Learn the SQL underneath
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 →Safe to experiment
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 →See how queries run
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 →Helpful as you type
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
Section titled “Start here” Install Get the playground running on your machine.
Your first project Create a table, add a row, and see it.
The example library The small database used throughout these docs.
Reference Every command, type, and constraint in detail.