Dataman is a fully multi-threaded database server and client API libraries in C, C++, Java, and a PHP module has now been added as well. This is a 'direct access' database, not a relational one. It emulates the verbs of the EDITOR language.
Build around JDBC and XML, this tool allows you to maintain visual repesentations of a database's layout, edit table's data, generate code to bind objects to tables, and export data in XML format to easely export data from one database to another.