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.
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.'
PhiloLogic is a full-text database engine developed for humanities computing text analysis by the ARTFL Project and the Digital Library Development Center at the University of Chicago. It is optimized for fast searching across very large collections of documents. It currently supports TEI-Lite, TEI XML, and TEI SGML documents.
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.
QML (Quantity Modeling Language) is a "thing"-based language for scientific and mathematical data modeling. Each "thing" is a quantity which may be associated with either a structure or physical phenomena. Quantities, in turn, may hold other Quantities or values (numbers or strings). Higher-level data models, which associate or define meanings to various quantities (such as velocity or position), can be built from QML quantities. The higher-level data model (XML) schema that inherits from QML may be understood, and its instance documents may be parsed into QML documents and objects by the QMLReader.