SQL schema diagrammer

What it does

Turn SQL table definitions into a diagram of tables, keys and declared relationships.

How to use it

1. Paste CREATE TABLE definitions, then draw and export JSON, Mermaid or SVG.
2. Processing stays in your browser. No upload or sign-up.

Example

The example users and posts tables produce one foreign-key relationship.

Methodology

A bounded CREATE TABLE subset extracts keys and foreign references; Mermaid renders synthetic identifiers with strict security.

Limitations

50,000 characters, 30 tables, 50 columns per table, 100 relationships. Simple identifiers and types only; comments, defaults, checks and dialect-specific clauses are rejected. Edges are schematic and do not infer cardinality. No connection or SQL execution.

Automation

This tool runs in your browser. No upload API or MCP endpoint is available.