Dublin Core Metadata Initiative

This document provides a set of draft W3C XML Schemas for the XML encoding conventions described in the Guidelines for implementing Dublin Core in XML.

The schemas take a modular approach in an effort to make them flexible to use. In particular, they seek to allow an application to select various subsets of Dublin Core terms in combination.

Dublin Core metadata applications are expected to develop their own application-specific XML schemes that 'import' the base schemas provided below:

• a "Simple DC" application, using only the 15 elements in the the http://purl.org/dc/elements/1.1/ namespace, would import only the dc.xsd schema,
• an "Unqualified DC" application, using all the "top-level elements" in the http://purl.org/dc/elements/1.1/ and http://purl.org/dc/terms/ namespaces (without the use of element refinements or encoding schemes from the latter namespace), would import the dc.xsd and dctermsu.xsd schemas,
• a "Qualified DC" application, using the elements from the http://purl.org/dc/elements/1.1/ namespace and both elements and element refinements from the http://purl.org/dc/terms/ namespaces, with both elements and refinements optionally associated with encoding schemes, would import the dc11q.xsd and dcterms.xsd schemas.

Note that the phrases "Simple DC", "Unqualified DC" and "Qualified DC" are used as follows:

Simple DC a metadata application that only uses the 15 elements defined in the http://purl.org/dc/elements/1.1/ namespace (15 elements). Unqualified DC a metadata application that only uses the elements defined in the http://purl.org/dc/elements/1.1/ namespace and any (top-level) elements in the http://purl.org/dc/terms/ namespace (currently 16 elements). Qualified DC a metadata application that only uses all the terms (elements and qualifiers) defined in the http://purl.org/dc/elements/1.1/ and http://purl.org/dc/terms/ namespaces (currently 16 elements plus DCMI recommended qualifiers). At present there is no consensus within DCMI on the usage of these phrases. They are used here only to indicate some of the aggregates of DCMI terms which might be required by metadata applications.

Base schemas

These base schemas are expected to be hosted on the DCMI Web site and imported into the schemas developed for DC metadata applications.

• Simple 15-element Dublin Core, no qualifiers
  (namespace: http://purl.org/dc/elements/1.1/ )
  dc.xsd
• 15-element Dublin Core, encoding schemes permitted
  (namespace: http://purl.org/dc/elements/1.1/ )
  dc11q.xsd
  • redefines complexTypes from dc.xsd
  • imports dcxml.xsd
  • redefines complexTypes from dctermsu.xsd
  • imports dc11q.xsd
  • imports dcxml.xsd

  Note that the dcxml.xsd supporting schema is not imported directly by an application schema, it is imported by the dc11q.xsd and dcterms.xsd base schemas.

  Examples from guidelines

  • some instance metadata (taken from the examples in Guidelines for implementing Dublin Core in XML),
  • an XML schema and
  • the W3C XSV validation tool.

  Instance metadata	XML schema	Validate using LTG's XSV @ W3C
  example4-3.xml (single resource, simple DC)	single1.xsd	Validate instance against single1.xsd output from XSV PSVI XML from XSV
  example5-3.xml (single resource, qualified DC)	single1q.xsd	Validate instance against single1q.xsd output from XSV PSVI XML from XSV
  example6-1.xml (single resource, simple DC, with IMS)	mixed1.xsd	Validate instance against mixed1.xsd output from XSV PSVI XML from XSV
  example6-2.xml (single resource, qualified DC, with IMS & ODRL)	mixed2.xsd	Validate instance against mixed2.xsd output from XSV PSVI XML from XSV
  example7.xml (compound resource, qualified DC, with IMS & vCard)	mixed3.xsd	Validate instance against mixed3.xsd output from XSV PSVI XML from XSV

  Notes

  • The schemas have taken a fairly "promiscuous" approach to the use of named complexTypes in the definition of elements, with the intention of giving applications the maximum flexibility in modifying/extending/redefining the complexTypes on which elements are based.
  • The schemas use the approach of defining some fixed attribute values (for xlink:role and dcxml:refines ) so that a validating parser will "decorate" the parse tree for an instance document with these additional nodes. (See the PSVI output from XSV in the examples above). This is something of an experiment (and may not be "good practice"), but may offer a means of providing information to the application on the relationship between refinements and elements.
  • In order to validate the instance metadata above, some of the schemas import locally 'cached' copies of non-DCMI schemas.
  • All the schemas conform to the W3C XML Schema specification.