fragment_downloaded_cb({"url":"defining-ontologies.html#defining-ontologies","fragment":"Defining ontologies\nAn ontology defines the entities that a Tracker endpoint can store, as\nwell as their properties and the relationships between different entities.\nTracker internally uses the following ontologies as its base, all ontologies\ndefined by the user of the endpoint are recommended to be build around this\nbase:\nOntologies are Turtle files with the .ontology extension, Tracker parses all\nontology files from the given directory. The individual ontology files may\nnot be self-consistent (i.e. use missing definitions), but\nall the ontology files as a whole must be.\nTracker loads the ontology files in alphanumeric order, it is advisable\nthat those have a numbered prefix in order to load those at a consistent\norder despite future additions.\n\nXML Schema (XSD), defining basic types\nResource Description Framework (RDF), defining classes, properties and\ninheritance\nNepomuk Resource Language (NRL), defining resource uniqueness, inheritance\nand indexes.\nDublin Core (DC), defining common superproperties for documents\n\n"});