drawDB
Free and open-source online database diagram editor and SQL generator. Design tables and relationships with drag-and-drop, then export DDL for MySQL, PostgreSQL, SQLite, MariaDB, or SQL Server. No sign-up required.
Relationship Map (atl2.net)
A web tool for creating relationship diagrams. Register people's photos and names to build a visual relationship map. Useful for tracking children's social connections and organizing interpersonal relationships.
システム構成図メーカー (toolpods.io)
Create flowcharts, sequence diagrams, class diagrams, and more using Mermaid syntax with real-time preview.
