XML-DBMS (Perl) is a port of the Java version of XML-DBMS. XML-DBMS is middleware for transferring data between XML documents and relational databases. It views the XML document as a tree of data-specific objects in which element types are generally viewed as classes and attributes and PCDATA as properties of those classes. It then uses an object-relational mapping to map these objects to the database. An XML-based mapping language is used to define the view and map it to the database.
The SODA Native XML Database System is a native XML database that provides efficient management of large amounts of XML data. It is based on a multi-user, client-server architecture with a generic query processing layer that can easily support different query languages. In this lightweight version, user- defined indexes and query optimizations have been removed, however full transaction support (commits and rollbacks) and crash recovery are available.
Tdbengine is an RDBMS with an integrated programming language. It represents the enhancement of the famous DOS-TDB, and is designed to handle databases on the Web. It connects to the Web server using the standard CGI interface, or runs on the command line. It is very small (about 400 KBytes), extremely quick, and easy to administrate. Its features are full text indexing, an automatic data link system, and the script language EASY, which replaces the commonly used SQL with its modular code.
HDB is a small, flexible, and efficient hybrid database, a mix between a filesystem and a database. It comes with a wide range of command line utilities for manipulating and extracting data. It's designed for both embedded and bigger systems. It currently has interfaces to C, C++, Java, and Perl.