eXist is a native XML database featuring efficient, index-based XPath query processing, extensions for keyword search, XUpdate support, and tight integration with existing XML development tools. The database is lightweight and may be easily deployed in a number of ways, running either as a stand-alone server process, inside a servlet engine, or directly embedded into an application.
Redland is a set of C libraries providing a high-level API for the Resource Description Framework (RDF), allowing it to be stored, parsed, serialized, queried, and manipulated. It has an object-based, modular design and comes with detailed reference documentation and examples. Redland supports all RDF vocabularies such as FOAF, RSS 1.0, Dublin Core, DOAP, and OWL, the query languages SPARQL and RDQL, and all RDF syntaxes including Turtle, RDF/XML, RDF/JSON, RSS, Atom, RDFa, and GRDDL.
XMLDB uses an RDBMS to persist arbitrary XML documents. Due to its storage mechanism, searching for and recalling documents is extremely quick. You can also perform XSL translation on documents with surprising speed. The library can be used in any program to store libxml2 documents. A PHP module is also included, making XMLDB into a complete three-tier Web application development suite.
MyHeadlines is module that adds syndicated headline functionality to any PHP and MySQL-based website. Your users may subscribe to multiple RSS feeds from a fully categorized database of over 1,000 sources. It was previously a PHPNuke/PostNuke Addon, but can now be integrated with any Web site.
Historical Event Markup and Linking Project (Heml) provides an XML schema for historical events and a Java Web app which transforms conforming documents into hyperlinked timelines, maps and tables. It aims to provide a most information-rich interchange format for historical data, and thus add a historical component to the growing movement for a 'Semantic Web.'
XPath Methods allows XPath queries on ParsedXML XML documents (and possibly other DOM implementations) in Zope. XPath is a relatively simple but still quite powerful query language used to address portions of XML documents. When you call an XPath Method you will retrieve a set of DOM nodes which you can then display in a Web page using DTML or ZPT, or which you can issue operations upon using, for instance, Python scripts.
LuMriX is a search engine that exploits XML and XML Topic Maps. In contrast to other retrieval methods, it does not relate single items to resources, but combines given items into meaningful associations (concepts), which are in turn linked to resources. XML Topic Maps allow an intelligent mapping of relations between terms and pages. The meaning of the query is captured by transverse joint relations between the search items. LuMriX is also able to auto-extend its thesaurus and create new relations between failed search items and information resources. It is completely implemented in Java. It can consist of many individual distributed LuMriX servers, which communicate with each other by distributed algorithms. Standardized interfaces such as TCP, SOAP, HTTP, XML, and XTM allow simple utilization and maintenance by other applications.