Tracker is a central repository of user information, that provides two big benefits for the desktop: Share data between applications (it doesn't matter the source once it is stored in the repository) and Link information from different sources (mixing contacts with files, location, activities and whatnot).
This central repository can work only with a very well defined data model, that applications can rely to store and recover their information. That data model is defined using a semantic web artifact called ontology. An ontology defines the concepts (classes) and properties (attributes) that the items in the repository can be/have.
There is an EU-funded project called Nepomuk, where a core of ontologies to model the Desktop were defined. This set was a very good starting point for Tracker but new requirements and heavy development in collaboration with applications provided a very valuable feedback, in form of fixes and extensions. Some of this work is already submitted for approval in the upstream version, but the process is long and hard, so the Tracker ontologies are diverging slowly.
This documentation describes the Tracker flavour of Nepomuk ontologies. The big picture and basic concepts are the same as in the original Nepomuk, but "hell and heaven are in the details". All classes, properties and restrictions included in these pages should work in Tracker. Any error in this documentation can be reported in the Tracker Mailing list or bugzilla.
This is just documentation about the ontologies. For more information about Tracker technical details and implementation, please refer to the Tracker Documentation wiki page in GNOME.
Table of Contents
- XML schema (XSD): Basic types definitions (int, double,...)
- Overview
- XSD Ontology Classes
- XSD Ontology Properties
- Resource Description Framework (RDF): Core RDF classes to keep the internal consistency of the ontology
- RDF Ontology Classes
- RDF Ontology Properties
- Dublin Core metadata (DC): Common superproperties for documents
- DC Ontology Classes
- DC Ontology Properties
- Nepomuk Information Element (NIE): Top classes in the ontology. Almost everything else is subclass of these.
- Overview
- NIE Ontology Classes
- NIE Ontology Properties
- Nepomuk Annotation Ontology (NAO): Tags, ratings and other common annotations to all classes
- NAO Ontology Classes
- NAO Ontology Properties
- Nepomuk File Ontology (NFO): About files and other desktop resources.
- NFO Ontology Classes
- NFO Ontology Properties
- Nepomuk Contacts Ontology (NCO): All about contacts. Rough equivalent of the VCARD standard.
- Overview
- NCO Ontology Classes
- NCO Ontology Properties
- Nepomuk Messaging Ontology (NMO): Model for messages and communications, including Email, SMS, MMS and phone calls
- Overview
- NMO Ontology Classes
- NMO Ontology Properties
- Nepomuk Calendar Ontology (NCAL): Automatic translation of the ICAL standard into ontology. Too complex for our taste. Please check SCAL
- NCAL Ontology Classes
- NCAL Ontology Properties
- Simplified Calendar Ontology (SCAL): Simple and efficient ontology to represent calendar information (events, ToDos, recurrency rules...)
- SCAL Ontology Classes
- SCAL Ontology Properties
- Nepomuk MultiMedia (NMM): Description of multimedia objects like Music, Video and Images
- Overview
- NMM Ontology Classes
- NMM Ontology Properties
- Maemo Transfer Ontology (MTO): Representation of download and upload operations in the system
- MTO Ontology Classes
- MTO Ontology Properties
- Maemo Location Ontology (MLO): Deprecated ontology for location and landmarks. Please check SLO
- Overview
- MLO Ontology Classes
- MLO Ontology Properties
- Maemo Feeds Ontology (MFO): Model for feeds and alike online streams
- Overview
- MFO Ontology Classes
- MFO Ontology Properties
- Multimetida Transfer Protocol (MTP) Ontology: Extra properties to add MTP information to the objects in the ontology
- MTP Ontology Classes
- MTP Ontology Properties
- Simplified Maemo Location Ontology (SLO) (experimental/for testing): Simpler, faster, better ontology for locations and landmarks
- SLO Ontology Classes
- SLO Ontology Properties
- Tracker-specific annotations Ontology: Internal tracker properties
- TRACKER Ontology Classes
- TRACKER Ontology Properties
- Maemo-specific classes: Some maemo/meego specific properties
- MAEMO Ontology Classes
- MAEMO Ontology Properties
- Full-text indexed properties in the ontology