One$DB: An Open Source Java Database - Version 4.0 One$DB is an Open Source version of Daffodil DB, an commercial Java Database. One$DB is a standards based (J2EE-certified, JDBC 3.0 and SQL 99 compliant), platform independent, footprint size open source database that can be embedded into any application and requires zero or minimal administration. One$DB can be easily deployed and embedded in a variety of Java-based applications. It has been made available in both Embedded and Network editions.