Latest Version: http://purl.org/rss/1.0/modules/dcterms/
Draft
Copyright © 2002 by the Authors.
Permission to use, copy, modify and distribute the RDF Site Summary 1.0 Specification and its accompanying documentation for any purpose and without fee is hereby granted in perpetuity, provided that the above copyright notice and this paragraph appear in all copies. The copyright holders make no representation about the suitability of the specification for any purpose. It is provided "as is" without expressed or implied warranty.
This copyright applies to the RDF Site Summary 1.0 Specification and accompanying documentation and does not extend to the RSS format itself.
This module is designed to allow Qualified Dublin Core metadata to be used in addition to the Dublin Core metadata that the RSS 1.0 Dublin Core module permits.
Dublin Core Qualifiers provides qualifiers for the Dublin Core Metadata Element Set, the Elements and Element Refinements - a current list document presents all current elements and element refinements maintained by the DCMI Usage Board. The namespace that this module uses is specified by the Dublin Core Namespace Policy.
Essential reference documents on the Dublin Core website include Guidelines for implementing Dublin Core in XML and the two DC RDF documents, Expressing Qualified Dublin Core in RDF / XML and Expressing Simple Dublin Core in RDF / XML.
This module's intention is to describe the simple content model -- if you wish to use a rich content model please refer to the Expressing Qualified Dublin Core in RDF / XML document on the DCMI web site, however be aware that RSS 1.0 does not allow elements to be repeated (see the Core Syntax section of the RSS 1.0 Specification), however this might change in the future -- currently the Bag, Seq and Alt RDF constructs must be used when repeating elements, again see the documentation on the DCMI web site for details.
This is an example of a date using the simple content model:
<dc:date>2000-01-01T12:00+00:00</dc:date>
Compared to a rich content model example (taken from Expressing Qualified Dublin Core in RDF):
<dc:date>
<dcterms:W3CDTF>
<rdf:value>1999-09-25T14:20+10:00</rdf:value>
</dcterms:W3CDTF>
</dc:date>
Since this module doesn't cover the use of complex content models the use of Encoding Schemes that used the dcterms: namespace is not covered except to suggest which encoding scheme should be used when none is specified as in the date example above.
<channel>, <item>, <image>, and <textinput> Elements:
The definition of DC Title and the qualifiers for DC Title can be found of the Dublin Core web site.
The RSS 1.0 <title> element is a sub-property of <dc:title> and as a result if <dc:title> is not present it can be assumed that <title> is also the <dc:title> for the element.
Alternative is a refined element which is a sub-property of the DC Title element and is defined as:
Name: alternative
Label: Alternative
Definition: Any form of the title used as a substitute or alternative to the formal title of the resource.
Comment: This qualifier can include Title abbreviations as well as translations.
For example a <item> element that linked to Slashdot could contain a <dcterms:alternative> element like this:
<dc:title>Slashdot</dc:title>
<dcterms:alternative>News for nerds, stuff that matters<dcterms:/alternative>
<dc:identifier rdf:resource="http://slashdot.org" />
The definition of DC Description and the qualifiers for DC Description can be found of the Dublin Core web site.
The RSS 1.0 <description> element is a sub-property of <dc:description> element.
Abstract is a refined element which is a sub-property of the DC Description element and is defined as:
Name: abstract
Label: Abstract
Definition: A summary of the content of the resource.
For example:
<dc:title>
XHTML™ 1.0 The Extensible HyperText Markup Language (Second Edition)
</dc:title>
<dcterms:astract>
This specification defines the Second Edition of XHTML 1.0, a reformulation of
HTML 4 as an XML 1.0 application, and three DTDs corresponding to the ones
defined by HTML 4. The semantics of the elements and their attributes are
defined in the W3C Recommendation for HTML 4. These semantics provide the
foundation for future extensibility of XHTML. Compatibility with existing HTML
user agents is possible by following a small set of guidelines.
<dcterms:abstract>
<dc:identifier rdf:resource="http://www.w3.org/TR/xhtml1/" />
Table Of Contents is a refined element which is a sub-property of the DC Description element and is defined as:
Name: tableOfContents
Label: Table Of Contents
Definition: A list of subunits of the content of the resource.
It is recommended that a URI be used to indicate the location of a Table Of Contents, for example:
<dc:title>RDF Site Summary (RSS) 1.0</dc:title>
<dcterms:tableOfContents rdf:resource="http://purl.org/rss/1.0/spec#toc" />
<dc:identifier rdf:resource="http://purl.org/rss/1.0/spec" />
The definition of DC Date and the qualifiers for DC Date can be found of the Dublin Core web site.
It is recommended that when Created is used it should be the date on which the document was first created, this will often be an earlier date than the Issued and Modified dates.
In addition Issued date should correspond to the date on which the document was publically made available, for example the date on which a document changes from being a private draft to being published on a web site.
For backwards compatability with RSS clients that support <dc:date> it is recommended that when the <dcterms:issued> element is used it should be in addition to a <dc:date> element and the <dc:date> element should have the same value as the <dcterms:issued> element.
Created is a refined element which is a sub-property of the DC Date element and is defined as:
Name: created
Label: Created
Definition: Date of creation of the resource.
The value of Created should be a date in W3C Date and Time Format.
For example:
<dc:title>Cool URIs don't change</dc:title>
<dcterms:created>1998</dcterms:created>
<dc:identifier rdf:resource="http://www.w3.org/Provider/Style/URI.html" />
Valid is a refined element which is a sub-property of the DC Date element and is defined as:
Name: valid
Label: Valid
Definition: Date (often a range) of validity of a resource.
The value of Valid should be a DCSV encoded DCMI Period. For example describing a resource that is only valid for the duration of a conference:
<dc:title>
DC-2002: Metadata for e-Communities: Supporting Diversity and Convergence
</dc:title>
<dcterms:valid>
name=DC-2002 - Metadata for e-Communities;
start=2002-10-13T09:00+01:00;
end=2002-10-17T17:00+01:00;
scheme=W3C-DTF
</dcterms:valid>
<dc:identifier rdf:resource="http://www.bncf.net/dc2002/" />
Avaliable is a refined element which is a sub-property of the DC Date element and is defined as:
Name: available
Label: Available
Definition: Date (often a range) that the resource will become or did become available.
The value of Avaliable should be a DCSV encoded DCMI Period.
For example describing a job advert:
<dc:title>
OO Perl / mod_perl programmer for Web CMS
</dc:title>
<dcterms:available>
name=OO Perl / mod_perl programmer for Web CMS;
start=2002-7-5;
end=2002-8-5;
scheme=W3C-DTF
</dcterms:available>
<dc:identifier rdf:resource="http://jobs.perl.org/job/373" />
Issued is a refined element which is a sub-property of the DC Date element and is defined as:
Name: issued
Label: Issued
Definition: Date of formal issuance (e.g., publication) of the resource.
For example:
<dc:title>Expressing Simple Dublin Core in RDF/XML</dc:title>
<dcterms:issued>2001-11-28</dcterms:issued>
<dc:identifier rdf:resource="http://dublincore.org/documents/2001/11/28/dcmes-xml/" />
Modified is a refined element which is a sub-property of the DC Date element and is defined as:
Name: modified
Label: Modified
Definition: Date on which the resource was changed.
It is recomended that the Modified date should correspond to the HTTP 1.1 Last-Modified date, of the document the <link> element points to when Modified is used withing a <item> element.
When Modified is used within the <channel> element it should correspond to the HTTP 1.1 Last-Modified date of the RSS feed and it is recomended that this should correspond to the date when the content of the feed changed, not the date when it was generated.
For example:
<dc:title>HTML 4.01 Specification</dc:title>
<dcterms:modified>1999-12-24</dcterms:modified>
<dc:identifier rdf:resource="http://www.w3.org/TR/html4/" />
Date Accepted is a refined element which is a sub-property of the DC Date element and is defined as:
Name: dateAccepted
Label: Date Accepted
Definition: Date of acceptance of the resource (e.g. of thesis by university department, of article by journal, etc.).
For example:
<dc:title>
Architectural Styles and the Design of Network-based Software Architectures
</dc:title>
<dcterms:dateAccepted>2000</dcterms:dateAccepted>
<dc:identifier rdf:resource="http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm" />
Date Copyrighted is a refined element which is a sub-property of the DC Date element and is defined as:
Name: dateCopyrighted
Label: Date Copyrighted
Definition: Date of a statement of copyright.
For example:
<dc:title>RDF Site Summary (RSS) 1.0</dc:title>
<dcterms:dateCopyrighted>2000</dcterms:dateCopyrighted>
<dc:identifier rdf:resource="http://purl.org/rss/1.0/spec" />
Date Submitted is a refined element which is a sub-property of the DC Date element and is defined as:
Name: dateSubmitted
Label: Date Submitted
Definition: Date of submission of the resource (e.g. thesis, articles, etc.).
For example:
<dc:title>My Thesis</dc:title>
<dcterms:dateSubmitted>2002</dcterms:dateSubmitted>
The definition of DC Format and the qualifiers for DC Format can be found of the Dublin Core web site.
Extent is a refined element which is a sub-property of the DC Format element and is defined as:
Name: extent
Label: Extent
Definition: The size or duration of the resource.
It is recomended that the value of Format should be the same as the HTTP 1.1 Content-Length header - the size of the document in bytes.
When Extent is used in a <channel> element is should be the value of the size of the RSS feed itself, when used within a <item> element it should be the size of the document that the <link> element points to.
For example these HTTP headers:
HTTP/1.1 200 OK Date: Thu, 22 Aug 2002 13:46:29 GMT Server: Apache/1.3.26 (Unix) mod_perl/1.27 mod_gzip/1.3.19.1a Last-Modified: Thu, 22 Aug 2002 13:46:29 GMT Connection: close Content-Location: http://mkdoc.com/ Content-Language: en-gb Content-Length: 19197 Content-Type: text/html; charset=UTF-8
Could be represented like this:
<dc:identifier rdf:resource="http://mkdoc.com/" />
<dc:lang>en-gb</dc:lang>
<dcterms:extent>19197</dcterms:extent>
<dcterms:format>text/html; charset=UTF-8</dcterms:format>
Medium is a refined element which is a sub-property of the DC Format element and is defined as:
Name: medium
Label: Medium
Definition: The material or physical carrier of the resource.
For example a book or CD could be the medium -- the medium should be something physical. Since RSS is used to describe web resources <dcterms:medium> is not obviously applicable.
For the Internet Media Type (MIME) of a resource either a unqualified dc:format should be used:
<dc:format>text/html</dc:format>
Or if a complex model is being adopted it should be done like this:
<dc:format>
<dcterms:IMT>
<rdf:value>text/html</rdf:value>
</dcterms:IMT>
</dc:format>
dcterms:medium should not be used for the MIME Type of the resource.
The definition of DC Relation and the qualifiers for DC Relation can be found of the Dublin Core web site.
Is Version Of is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: isVersionOf
Label: Is Version Of
Definition: The described resource is a version, edition, or adaptation of the referenced resource. Changes in version imply substantive changes in content rather than differences in format.
It is recommended that the value of Is Version Of should be a URI.
For example:
<dc:title>HTML 4.0 Specification</dc:title>
<dc:date>1997-12-18</dc:date>
<dc:identifier rdf:resource="http://www.w3.org/TR/REC-html40-971218/" />
<dcterms:isVersionOf rdf:resource="http://www.w3.org/TR/REC-html40" />
Has Version is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: hasVersion
Label: Has Version
Definition: The described resource has a version, edition, or adaptation, namely, the referenced resource.
It is recommended that the value of Has Version should be a URI.
For example:
<dc:title>HTML 4.0 Specification</dc:title>
<dc:date>1998-04-24</dc:date>
<dc:identifier rdf:resource="http://www.w3.org/TR/1998/REC-html40-19980424/" />
<dcterms:hasVersion rdf:resource="http://www.w3.org/TR/REC-html40-971218/" />
Is Replaced By is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: isReplacedBy
Label: Is Replaced By
Definition: The described resource is supplanted, displaced, or superceded by the referenced resource.
It is recommended that the value of Is Replaced By should be a URI.
For example:
<dc:title>HTML 4.0 Specification</dc:title>
<dc:date>1998-04-24</dc:date>
<dc:identifier rdf:resource="http://www.w3.org/TR/1998/REC-html40-19980424/" />
<dcterms:isReplacedBy rdf:resource="http://www.w3.org/TR/html401" />
Replaces is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: replaces
Label: Replaces
Definition: The described resource supplants, displaces, or supersedes the referenced resource.
It is recommended that the value of Replaces should be a URI.
For example:
<dc:title>HTML 4.01 Specification</dc:title>
<dc:date>1999-08-24</dc:date>
<dc:identifier rdf:resource="http://www.w3.org/TR/REC-html401" />
<dcterms:replaces rdf:resource="http://www.w3.org/TR/1998/REC-html40-19980424/" />
Is Required By is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: isRequiredBy
Label: Is Required By
Definition: The described resource is required by the referenced resource, either physically or logically.
It is recommended that the value of Is Required By should be a URI.
For example:
<dc:title>RSS CSS Stylesheet</dc:title>
<dc:identifier rdf:resource="http://purl.org/rss/1.0/style" />
<dcterms:isRequiredBy rdf:resource="http://purl.org/rss/1.0/" />
Requires is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: requires
Label: Requires
Definition: The described resource requires the referenced resource to support its function, delivery, or coherence of content.
It is recommended that the value of Requires should be a URI.
For example:
<dc:title>RDF Site Summary (RSS) 1.0</dc:title>
<dc:identifier rdf:resource="http://purl.org/rss/1.0/" />
<dcterms:requires rdf:resource="http://purl.org/rss/1.0/style" />
Is Part Of is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: isPartOf
Label: Is Part Of
Definition: The described resource is a physical or logical part of the referenced resource.
It is recommended that the value of Is Part Of should be a URI.
For example:
<dc:identifier rdf:resource="http://images.slashdot.org/title.gif" />
<dc:format>image/gif</dc:format>
<dcterms:isPartOf rdf:resource="http://slashdot.org/" />
Has part is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: hasPart
Label: Has Part
Definition: The described resource includes the referenced resource either physically or logically.
It is recommended that the value of Has Part should be a URI.
For example:
<dc:identifier rdf:resource="http://slashdot.org/" />
<dc:format>text/html</dc:format>
<dcterms:hasPart rdf:resource="http://images.slashdot.org/title.gif" />
Is Referenced By is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: isReferencedBy
Label: Is Referenced By
Definition: The described resource is referenced, cited, or otherwise pointed to by the referenced resource.
It is recommended that the value of Is Referenced By should be a URI.
For example:
<dc:identifier rdf:resource="http://www.w3.org/TR/REC-rdf-syntax" />
<dc:title>
Resource Description Framework
(RDF) Model and Syntax Specification
</dc:title>
<dcterms:isReferencedBy rdf:resource="http://dublincore.org/documents/dcmes-xml/" />
References is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: references
Label: References
Definition: The described resource references, cites, or otherwise points to the referenced resource.
It is recommended that the value of References should be a URI.
For example:
<dc:identifier rdf:resource="http://dublincore.org/documents/dcmes-xml/" />
<dc:title>Expressing Simple Dublin Core in RDF/XML</dc:title>
<dcterms:references rdf:resource="http://www.w3.org/TR/REC-rdf-syntax" />
Is Format Of is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: isFormatOf
Label: Is Format Of
Definition: The described resource is the same intellectual content of the referenced resource, but presented in another format.
It is recommended that the value of Is Format Of should be a URI.
For example:
<dc:identifier rdf:resource="http://www.w3.org/TR/WCAG10/wai-pageauth.txt" />
<dc:title>Web Content Accessibility Guidelines 1.0</dc:title>
<dc:format>text/plain</dc:format>
<dcterms:isFormatOf rdf:resource="http://www.w3.org/TR/WCAG10/" />
Has Format is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: hasFormat
Label: Has Format
Definition: The described resource pre-existed the referenced resource, which is essentially the same intellectual content presented in another format.
It is recommended that the value of Has Format should be a URI.
For example:
<dc:identifier rdf:resource="http://www.w3.org/TR/WCAG10/" />
<dc:title>Web Content Accessibility Guidelines 1.0</dc:title>
<dc:format>text/html</dc:format>
<dcterms:hasFormat rdf:resource="http://www.w3.org/TR/WCAG10/wai-pageauth.txt" />
Conforms To is a refined element which is a sub-property of the DC Relation element and is defined as:
Name: conformsTo
Label: Conforms To
Definition:A reference to an established standard to which the resource conforms.
It is recommended that the value of Has Format should be a URI, for example, for a XHTML document:
<dcterms:conformsTo rdf:resource="http://www.w3.org/TR/xhtml1/" />
Or for a document that achieves WAI WCAG AA:
<dcterms:conformsTo rdf:resource="http://www.w3.org/WAI/WCAG1AA-Conformance" />
The definition of DC Coverage and the qualifiers for DC Coverage can be found of the Dublin Core web site.
Spatial is a refined element which is a sub-property of the DC Coverage element and is defined as:
Name: spatial
Label: Spatial
Definition: Spatial characteristics of the intellectual content of the resoure.
There are several encoding schemes for Spatial, several of which could be the default one for RSS. However since it's not clear which one it is recommended that if Spatial is used it's encoding scheme is made clear for example:
<dcterms:spatial>
<dcterms:Point>
<rdf:value>
name="KS, Topeka"; projection=WGS84; north=39.04; east=-95.69
</rdf:value>
</dcterms:Point>
</dcterms:spatial>
<dcterms:spatial>
<dcterms:Box>
<rdf:value>
name=Western Australia;
northlimit=-13.5; southlimit=-35.5;
westlimit=112.5; eastlimit=129
</rdf:value>
</dcterms:Box>
</dcterms:spatial>
<dcterms:spatial>
<dcterms:TNG>
<rdf:value>7008171</rdf:value>
<rdf:label>Yorkshire (region (general))</rdf:label>
</dcterms:TNG>
</dcterms:spatial>
Temporal is a refined element which is a sub-property of the DC Coverage element and is defined as:
Name: temporal
Label: Temporal
Definition: Temporal characteristics of the intellectual content of the resource.
The value of Temporal should be a DCSV encoded DCMI Period, for example:
<dcterms:temporal> name=The Great Depession; start=1929; end=1939; scheme=W3C-DTF </dcterms:temporal>
DC elements that use the DC Terms namespace that are not sub-properties of the core 15 elements.
Audience is defined as:
Name: audience
Label: Audience
Definition: A class of entity for whom the resource is intended or useful.
For example:
<dc:title>Slashdot</dc:title>
<dc:identifier rdf:resource="http://slashdot.org/" />
<dcterms:audience>geeks, linux users<dcterms:audience>
Mediator is defined as:
Name: mediator
Label: Mediator
Definition: A class of entity that mediates access to the resource and for whom the resource is intended or useful.
Sorry I can't think of an example for this element.
<?xml version="1.0" encoding="UTF-8"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://purl.org/rss/1.0/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/"> <channel rdf:about="http://www.example.com/"> <title>Example.com</title> <link>http://www.example.com/</link> <description>This web site is all about examples.</description> <dc:language>en</dc:language> <dc:date>2002-06-21T20:24:55Z</dc:date> <dc:publisher>Example Ltd.</dc:publisher> <dc:creator>Chris Croome</dc:creator> <items> <rdf:Seq> <rdf:li rdf:resource="http://www.example.com/2002/06/26/" /> </rdf:Seq> </items> </channel> <item rdf:about="http://www.example.com/2002/06/26/"> <title>Qualified DC RSS</title> <link>http://www.example.com/2002/06/26/</link> <description>Todays example illustrates how to use Qualified Dublin Core metadata with RSS 1.0</description> <dc:creator>Chris Croome</dc:creator> <dc:language>en</dc:language> <dc:language>en</dc:language> <dc:date>2002-06-26T11:55:20Z</dc:date> <dc:format>text/html</dc:format> <dcterms:created>2002-06-26T11:17:35Z</dcterms:created> <dcterms:issued>2002-06-26T11:55:20Z</dcterms:issued> <dcterms:modified>2002-06-26T14:07:01Z</dcterms:modified> <dcterms:conformsTo rdf:resource="http://www.w3.org/TR/xhtml1/" /> </item> <textinput rdf:about="http://www.example.com/search.html"> <title>Search</title> <description>Use this form to search Example.com</description> <name>q</name> <link>http://www.example.com/search.html</link> </textinput> </rdf:RDF>
There are several common mistakes that are made when producing Dublin Core RSS metadata.
One important difference between using Dublin Core metadata in RSS when compared to (X)HTML is that the nesting of qualifiers within elements is not something that should be done, for example this qualified XHTML Dublin Core metadata :
<meta name="DC.Date.modified" scheme="W3C-DTF" content="2002-Sep-25T20:33:04Z" />
Should not be written like this for RSS:
<dc:date> <dcterms:modified>2002-Sep-25T20:33:04Z</dcterms:modified> </dc:date>
It can however be written like this:
<dcterms:modified>
<dcterms:W3CDTF>
<rdf:value>2002-Sep-25T20:33:04Z</rdf:value>
</dcterms:W3CDTF>
</dcterms:modified>
This makes the encoding scheme, W3C Date Time Format, explicit, however since W3CDTF is the default for RSS a simpler syntax can be used:
<dcterms:modified>2002-Sep-25T20:33:04Z</dcterms:modified>
The RFC for Dublin Core in HTML uses capitalised element names seperated with dots, for example, DC.Relation this should not be done in RSS, colons should be used and elements should start with a lower case letter, for example, dc:relation.
For a while the namespace prefix dcq was suggested by the DCMI for refined elements, however this should not be used, dcterms is the correct namespace prefix to use.
Do not use URIs as literals:
<dc:identifier>http://example.org/</dc:identifier>
Do not use the URI encoding schema:
<dc:identifier>
<dcterms:URI>
<rdf:value>http://example.org/</rdf:value>
<dcterms:URI>
</dc:identifier>
Instead use the RDF syntax for URIs:
<dc:identifier rdf:resource="http://example.org/" />