At no charge, DB2 Express-C is also 98% compatible with Oracle Database. The database compatibility feature includes support for PL/SQL, CLP+, and much more. Use it for production, test, or development.
You can redistribute DB2 Express-C at no charge as the database solution for your application. Though it will limit itself to only consuming a set amount of your computing resources, DB2 Express-C has no limitations on database size, number of users, or your preferred uses.
This is a great opportunity to learn databases, learn SQL, or learn DB2.