Redfoot framework for building distributed data-driven web applications with RDF and Python http://redfoot.sourceforge.net/

RDFStore PERL API for RDF storage http://rdfstore.sourceforge.net/

Redland RDF Application Framework library which provides a high-level interface for storing, querying and manipulating the RDF data model http://www.redland.opensource.ac.uk/

Jena semantic web toolkit java API for manipulating RDF models, uses Berkeley DB (Sleepycat) for storage and also offers support for relational databases http://www.hpl.hp.com/semweb/jena-top.html

TEXTML native XML database server for content search and retrieval, supports WAP http://www.ixiasoft.com/