MarkLogic is a multi-model DBMS that supports document (XML) and graph (RDF) data.
Document / XML Triplestore / RDF
Custom API
http://www.marklogic.com/
https://www.marklogic.com/resources/
@MarkLogic
MarkLogic
US
2001
Cerisent
Vector Capital
Commercial
Proprietary
https://en.wikipedia.org/wiki/MarkLogic