Fedora can store metadata in any format, including common formats like XML and JSON. Additionally, Fedora enables RDF properties to be defined for objects it stores or references. This includes all types of metadata, such as technical, rights, provenance, and descriptive. Managing this metadata in Fedora means considering how best to make use of RDF and Linked Data. Some access systems such as Hyrax or Islandora also provide editing and management capabilities for RDF metadata stored as properties in Fedora. See Common metadata design patterns for examples of ways to take advantage of Fedora's capabilities.
Fedora uses a set of internal properties (see http://fedora.info/definitions/v4/repository) and supplies the following ontologies by default.
premis: http://www.loc.gov/premis/rdf/v1# test: info:fedora/test/ memento: http://mementoweb.org/ns# rdfs: http://www.w3.org/2000/01/rdf-schema# webac: http://fedora.info/definitions/v4/webac# acl: http://www.w3.org/ns/auth/acl# vcard: http://www.w3.org/2006/vcard/ns# iana: http://www.iana.org/assignments/relation/ xsi: http://www.w3.org/2001/XMLSchema-instance xmlns: http://www.w3.org/2000/xmlns/ rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns# fedora: http://fedora.info/definitions/v4/repository# xml: http://www.w3.org/XML/1998/namespace ebucore: http://www.ebu.ch/metadata/ontologies/ebucore/ebucore# ldp: http://www.w3.org/ns/ldp# dcterms: http://purl.org/dc/terms/ xs: http://www.w3.org/2001/XMLSchema fedoraconfig: http://fedora.info/definitions/v4/config# foaf: http://xmlns.com/foaf/0.1/ dc: http://purl.org/dc/elements/1.1/
This is a configurable list provided within the Fedora codebase: https://github.com/fcrepo4/fcrepo4/blob/master/fcrepo-webapp/src/main/resources/namespaces.yml
It is possible to include and use any ontology that exists, although it is recommended to use ontologies that are shown to be currently active and well-maintained for longevity purposes.
The Samvera Community and Islandora Community have developed metadata recommendations, including mapping recommendations for objects currently defined with metadata using XML.
Metadata Recommendations:
- Samvera Community - Technical Metadata Application Profile
- Samvera Community - Rights Metadata Recommendation
- Samvera Community - Referring to segments of a file - Recommendation
- Samvera Community - Decision Tree for New Predicates/Vocabularies
- Samvera Community - MODS to RDF Mapping Recommendations - This mapping recommendation offers two paths to transition MODS descriptive XML to RDF properties:
- A direct mapping that provides single RDF statements for MODS concepts without any hierarchy or complexity of graphed relationships. Some MODS attributes and level of detail is lost but these statements can be managed directly with the Fedora object.
- A minted object mapping that preserves the hierarchy and complexity of MODS concepts by creating (minting) new objects for subjects, names, and other descriptive elements representing a graphed relationship. Creates empty objects in the digital repository but MODS attributes and details are preserved.
Additional Works in Progress
- Islandora Community - MODS to RDF Mapping Recommendations (work in progress)
