ER/Builder Data Modeler is free for students and non-profit organisations. It allows developers to design or modify databases and supports creating entity relationship diagrams.
Supported databases: Oracle, MS SQL Server, PostgreSQL, MySQL, SQLite and Firebird.
Ranked in these QuestionsQuestion Ranking
Pro Ease of use
Pro Supports many databases
Pro ER Builder is aasy to use and a complete modeling tool
Very interesting tool, powerful and easy to use. Can do reverse and forward engineering, generate SQL script, and more.
Only 8 Mb install size.
Pro Not limited
The free version does not seem limited (for personal use).