Nepomuk Contacts Ontology (NCO): All about contacts. Rough equivalent of the VCARD standard.

  • Tracker Developers
  • Ludger van Elst, DFKI, <>
  • Michael Sintek, DFKI, <>
  • Leo Sauermann, DFKI, <>
  • Antoni Mylka, DFKI, <>
  • Antoni Mylka, DFKI, <>
  • Tracker developers (translation into turtle)
  • Christiaan Fluit, Aduna, <>
  • Evgeny 'phreedom' Egorochkin, KDE Strigi Developer, <>

Upstream version


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© 2007 DFKI © 2009 Nokia. The ontologies are made available under the terms of NEPOMUK software license (FIXME verify)



This is the ontology modelling contacts and postal addresses. It also extends the original nepomuk adding the Instant Messaging account details, because an 'identity' in an IM account can be consider also a contact.

FIXME This documentation must be completed.

A contact in this ontology

Document here how a contact with work and personal details is represented in the ontology. So far the QtContacts API is using this model to store the information internally, document here all the assumptions they are doing in the code, so a client using pure Sparql is completely compatible with that information

Do not forget contact groups and affiliations

Postal Address

Postal address class nco:PostalAddress represents a point in the space defined by the usual street, number, postal code textual data. Most of its parameters come from the RFC 2426 section 3.2.1 with few extensions for more granular APIs (nco:county and nco:district)

IM Accounts and contacts

Explain here how to represent the accounts of 'me' and the contacts coming from the accounts. Do not forget to explain how do we merge the same user in different accounts under one 'identity'. Also the authorization flow.

Special remarks

Maybe we need to add here something

Related information

Links to external docs (QT-contacts, Qt-Landmarks would be nice)