Pireal 1.0 - Relational Algebra query evaluator
Pireal is a tool for working with relational algebra. You can create a database, add/edit relationships and run queries, all from an intuitive interface. It's cross-platform and is available in English and Spanish, but can be extended to another language easily.
Pireal was intended for use in educational institutions for learning relational algebra.
Installer for Windows: pireal-1.0-installer.exe
Source Code: source