Eprints DC XML
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Introduction
This document specifies an XML format for representing a DC metadata description set. This XML format is known as "Eprints-DC-XML". It is based closely on a working draft of the Architecture Working Group for an XML format for representing DC metadata [DCXMLFULL]. The format described in this document does not have any status witin the DCMI.
The DCMI Abstract Model and Eprints-DC-XML
Readers that are not familiar with the DCMI Abstract Model [DCAM] should read A note about the DCMI Abstract Model.
According to the DCAM description model:
- a description set is made up of one or more descriptions
- a description is made up of
- zero or one resource URI and
- one or more statements
- a statement is made up of
- exactly one property URI and
- zero or one reference to a value in the form of a value URI
- zero or more representations of a value, each in the form of a value representation
- zero or one vocabulary encoding scheme URI
- a value representation is either
- a value string or
- a rich representation
- a value string may be associated with either a value string language or a syntax encoding scheme URI
- a value may be the described resource of another description in the description set
The Eprints-DC-XML format described in this document implements all the features of the DCAM description model.
The Eprints-DC-XML Syntax
URIs in Eprints-DC-XML
The DCAM description model uses Uniform Resource Identifiers (URIs) [RFC3986] to refer both to resources described within DC metadata description sets and to the metadata terms (properties,classes, vocabulary encoding schemes and syntax encoding schemes) used in those description sets.
In Eprints-DC-XML, those URIs are encoded as XML attribute values. Later sections of this document describe the use of those different XML attributes in detail. The purpose of this section is to make some general points about the representation of these URIs in Eprints-DC-XML.
In Eprints-DC-XML, URIs are encoded as URI references, used as XML attribute values. A URI reference is either a URI or a relative reference [RFC3986].
The URI may be represented in full. The following example shows a URI as the value of the epdcx:propertyURI attribute:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description> <-- Property URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 1: URI as attribute value
The representation of the URI may be abbreviated through the use of an XML entity reference as follows, for example:
<?xml version="1.0"?> <!DOCTYPE epdcx:descriptionSet [ <!ENTITY dc 'http://purl.org/dc/elements/1.1/'> ]> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description> <-- Property URI using XML entity reference --> <epdcx:statement epdcx:propertyURI="&dc;title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 2: URI as attribute value (with XML entity reference)
Note: the use of XML entity references requires the presence of a suitable entity declaration in the internal subset of the XML document. Where an Eprints-DC-XML instance is embedded within another XML format (e.g. when the instance is contained within an<oai:metadata> element in an OAI-PMH response message), the generation of an internal subset may be outside of the control of the metadata application.
For all of the attributes in Eprints-DC-XML which have URIs as values, the value may also be a relative reference. The relative reference is resolved relative to a base URI, obtained either from the value of an xml:base attribute or from the URI of the document itself. In the following example, the value of the epdcx:propertyURI attribute is a relative reference. It is resolved relative to the base URI provided by the xml:base attribute to obtain a target URI of http://purl.org/dc/elements/1.1/title:
<?xml version="1.0"?> <epdcx:descriptionSet xml:base="http://purl.org/dc/elements/1.1/" xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description> <-- Property URI as relative reference --> <epdcx:statement epdcx:propertyURI="title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 3: Relative reference as attribute value
Encoding a Description Set: The Description Set Element
A description set is a set of one or more descriptions.
In Eprints-DC-XML, a description set is represented by an XML element known as a Description Set Element (See Note 2). A Eprints-DC-XML instance represents a single DC description set, so has exactly one Description Set Element.
A Description Set Element has an expanded name (XML Namespace Name/local name pair) with the XML Namespace Name http://purl.org/eprint/epdcx/2006-11-16/ and local name descriptionSet.
In the examples presented in this document, the XML Namespace Name http://purl.org/eprint/epdcx/2006-11-16/ is always associated with the prefix "epdcx". For convenience, after this point, the names of XML elements and XML attributes are presented in the text as XML QNames (e.g. epdcx:descriptionSet, epdcx:resourceURI), rather than as expanded names, but they should be read as XML expanded names: the prefix used is not significant.
<?xml version="1.0"?>
<-- Description Set Element -->
<epdcx:descriptionSet
xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/">
<epdcx:description>
<epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title">
<epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString>
</epdcx:statement>
</epdcx:description>
</epdcx:descriptionSet>
XML Example 4: The Description Set Element
The Description Set Element must contain one or more Description Elements.
Encoding Descriptions: Description Elements
A description is a set of one or more statements about a resource.
In Eprints-DC-XML, a description is represented by an XML element known as a Description Element. A Description Element is a child element of a Description Set Element and has the name epdcx:description.
The following example shows a description set consisting of a single description:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <-- Description Element --> <epdcx:description> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 5: A Description Element
A description set may contain multiple descriptions.
In Eprints-DC-XML, each description is represented by a separate Description Element. The order of the Description Elements within a Description Set Element is not significant.
The following example shows a description set consisting of two descriptions:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <-- 1st Description Element --> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> </epdcx:description> <-- 2nd Description Element --> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/expressions/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/Expression" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/language" epdcx:vesURI="http://purl.org/dc/terms/RFC3066"> <epdcx:valueString>en</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 6: Multiple Description Elements
The encoding of description sets with multiple descriptions is described further in Encoding Descriptions of Values.
A Description Element may have various attributes and it must contain one or more Statement Elements.
The Resource URI
A description may have an associated resource URI.
In Eprints-DC-XML, a resource URI is represented as the value of an XML attribute of the Description Element. The attribute has the name epdcx:resourceURI.
The example below shows a description with the resource URI http://eprints.bath.ac.uk/works/12345678/.
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <-- resource URI --> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> </epdcx:description> </epdcx:descriptionSet>
XML Example 7: The Resource URI Attribute
Note that the representation of the resource URI may be abbreviated through the use of an XML entity reference or a URI relative reference (see URIs in Eprints-DC-XML).
Encoding Statements: Statement Elements
A description is made up of one or more statements.
In Eprints-DC-XML, each child XML element of a Description Element represents a single statement and is known as a Statement Element. A Statement Element always has the name epdcx:statement.
The following example shows description set with a single description consisting of a single statement:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <-- Statement Element --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 8: A Statement Element
A description may be made up of multiple statements, each represented by a separate Statement Element. The order of the Statement Elements within a Description Element is not significant.
The following example shows description set with a single description consisting of three statements:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <-- 1st Statement Element --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <-- 2nd Statement Element --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <-- 3rd Statement Element --> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> </epdcx:description> </epdcx:descriptionSet>
XML Example 9: Multiple Statement Elements
A Statement Element may have various attributes and it may contain zero or more Value Representation Elements.
The Property URI
A statement must contain exactly one property URI.
In Eprints-DC-XML, a property URI is represented as the value of an XML attribute of the Statement Element. The attribute has the name epdcx:propertyURI.
The example below shows a description consisting of three statements where the property URIs are http://purl.org/dc/elements/1.1/type, http://purl.org/dc/elements/1.1/title and http://purl.org/eprint/terms/isExpressedAs.
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <-- property URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <-- property URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <-- property URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> </epdcx:description> </epdcx:descriptionSet>
XML Example 10: The Property URI Attribute
Note that the representation of the property URI may be abbreviated through the use of an XML entity reference or a URI relative reference (see URIs in Eprints-DC-XML).
The Value URI
A statement may contain a value URI.
In Eprints-DC-XML, a value URI is represented as the value of an XML attribute of the Statement Element. The attribute has the name epdcx:valueURI.
The example below shows a description consisting of three statements where the first statement includes the value URI http://purl.org/eprint/entityType/ScholarlyWork and the third statement includes the value URI http://eprints.bath.ac.uk/expressions/12345678/.
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <-- value URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <-- value URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> </epdcx:description> </epdcx:descriptionSet>
XML Example 11: The Value URI Attribute
The representation of the value URI may be abbreviated through the use of an XML entity reference or a URI relative reference (see URIs in Eprints-DC-XML).
The Vocabulary Encoding Scheme URI Attribute
A statement may include a vocabulary encoding scheme URI.
In Eprints-DC-XML, a vocabulary encoding scheme URI is represented as the value of an XML attribute of the Statement Element. The attribute has the name epdcx:vesURI.
The example below shows a description consisting of four statements where the third statement includes the vocabulary encoding scheme URI http://purl.org/dc/terms/LCSH.
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> <-- vocabulary encoding scheme URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/subject" epdcx:vesURI="http://purl.org/dc/terms/LCSH"> <epdcx:valueString>Genetics</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 12: The Vocabulary Encoding Scheme URI Attribute
Note that the representation of the vocabulary encoding scheme URI may be abbreviated through the use of an XML entity reference or a URI relative reference (see URIs in Eprints-DC-XML).
Encoding Value Strings and Rich Representations: Value Representation Elements
A statement may contain zero or more value representations.
In Eprints-DC-XML, the value representations are represented by child elements of the Statement Element known as Value Representation Elements. The order of the Value Representation Elements within a Statement Element is not significant.
A value representation may take the form of a value string or a rich representation
Empty Statement Elements
The presence of a value representation in a statement is optional.
In Eprints-DC-XML, the Statement Element may therefore be empty.
The example below shows a description consisting of four statements where the first statement and the third statement provide a value URI but no value representation.
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <-- statement with no value representation --> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <-- statement with no value representation --> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/subject" epdcx:vesURI="http://purl.org/dc/terms/LCSH"> <epdcx:valueString>Genetics</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 13: Empty Statement Element
The Value String
A value string is represented by an XML element with the element name epdcx:valueString.
The example below shows a description consisting of four statements of which the second and fourth statements each include a value string.
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <-- value string --> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/subject" epdcx:vesURI="http://purl.org/dc/terms/LCSH"> <-- value string --> <epdcx:valueString>Genetics</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 14: The Value String
A statement may contain multiple value strings, each represented by a separate epdcx:valueString child XML element.
The following example shows description set with two descriptions. The first description consists of five statements of which the third statement provides three value strings'; the second description consists of xxx statements of which the xxx statement provides two value strings'
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/terms/abstract"> <-- 1st value string --> <epdcx:valueString>The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.</epdcx:valueString> <-- 2nd value string --> <epdcx:valueString>Le génome humain....</epdcx:valueString> <-- 3rd value string --> <epdcx:valueString>El genoma humano....</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/subject" epdcx:vesURI="http://purl.org/dc/terms/LCSH"> <epdcx:valueString>Genetics</epdcx:valueString> </epdcx:statement> </epdcx:description> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/expressions/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/Expression" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/language" epdcx:vesURI="http://purl.org/dc/terms/RFC3066"> <epdcx:valueString>en</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/terms/abstract"> <-- 1st value string --> <epdcx:valueString>Lander ES, Linton LM, Birren B, Nusbaum C, Zody MC, et al. (2001) Initial sequencing and analysis of the human genome. Nature 409: 860--921.</epdcx:valueString> <-- 2nd value string --> <epdcx:valueString>ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal &rft.jtitle=Nature&rft.volume=409=1&rft.spage=860&rft.epage=921 &rft.atitle=Initial sequencing and analysis of the human genome &rft.aulast=Lander&rft.auinit=ES&rft.date=2000 &rfr_id=....</epdcx:valueString> </epdcx:statement> </epdcx:description>
</epdcx:descriptionSet>
XML Example 15: Multiple Value Strings
The Value String Language
A value string may have an associated value string language.
In Eprints-DC-XML, a value string language is represented by an xml:lang attribute of the epdcx:valueString XML element representing the value string.
The example below shows a description consisting of five statements where the third statement provides three value strings and each has an associated value string language:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/terms/abstract"> <-- value string language --> <epdcx:valueString xml:lang="en">The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.</epdcx:valueString> <-- value string language --> <epdcx:valueString xml:lang="fr">Le génome humain....</epdcx:valueString> <-- value string language --> <epdcx:valueString xml:lang="es">El genoma humano....</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/subject" epdcx:vesURI="http://purl.org/dc/terms/LCSH"> <epdcx:valueString>Genetics</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 16: The Value String Language
The Syntax Encoding Scheme URI
A value string may have an associated syntax encoding scheme URI.
In Eprints-DC-XML, a syntax encoding scheme URI is represented as the value of an attribute of the the epdcx:valueString XML element representing the value string. The attribute has the name epdcx:sesURI.
The example below shows a description set in which the second description has three statements and the third statement associates the syntax encoding scheme URI http://purl.org/dc/terms/W3CDTF with the value string "2004-09-23":
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> </epdcx:description> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/expressions/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/Expression" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/language" epdcx:vesURI="http://purl.org/dc/terms/RFC3066"> <epdcx:valueString>en</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/terms/available"> <-- syntax encoding scheme URI --> <epdcx:valueString epdcx:sesURI="http://purl.org/dc/terms/W3CDTF">2004-09-23</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 17: The Syntax Encoding Scheme URI Attribute
Note that the representation of the syntax encoding scheme URI may be abbreviated through the use of an XML entity reference or a URI relative reference (see URIs in Eprints-DC-XML).
Rich Representations
A value may also be represented by a rich representation - i.e. by some XML data or by a binary data object.
XML Data
An XML data rich representation is represented by the content of a Value Representation Element with the element name epdcx:XMLRepresentation.
The example below shows a description consisting of five statements of which the third statement includes both a value string and a rich representation of the value in the form of an XML fragment:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/terms/abstract"> <epdcx:valueString>The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.</epdcx:valueString> <-- XML data --> <epdcx:XMLRepresentation> <div xmlns="http://www.w3.org/1999/xhtml"> <p>The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence. </p> </div> </epdcx:XMLRepresentation> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/subject" epdcx:vesURI="http://purl.org/dc/terms/LCSH"> <epdcx:valueString>Genetics</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 18: Rich Representation - XML Data
Binary Data
A binary data rich representation is represented by the content of a Value Representation Element with the element name epdcx:binaryRepresentation. The XML element content is a Base64 encoding of the binary object. The media type of the rich representation is represented by the value of an attribute of the Value Representation Element. The attribute has the name epdcx:mediaType, and the value must be a MIME Media Type.
The example below shows a description consisting of two statements of which the second statement includes a rich representation of the value in the form of a binary data object:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://dublincore.org/pages/home"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString xml:lang="en-GB">DCMI Home Page</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/description"> <-- binary data --> <epdcx:binaryRepresentation epdcx:mediaType="image/png">AABBCCDDEEFF</epdcx:binaryRepresentation> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 19: Rich Representation - Binary Data
Encoding Descriptions of Values
As noted in Encoding Descriptions: Description Elements, description sets may contain multiple descriptions. Each description is represented by a separate Description Element. The order of the Description Elements has no significance.
It may be that the resource which is a value in a statement in one description is the described resource of another description within the description set. If that resource has been assigned a URI, then that URI appears as the value URI in the statement where the resource is the value and as a resource URI in the description of that resource, as shown below:
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <-- value URI --> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueURI="http://eprints.bath.ac.uk/expressions/12345678/" /> </epdcx:description> <-- value URI used as resource URI in separate description --> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/expressions/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/Expression" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/language" epdcx:vesURI="http://purl.org/dc/terms/RFC3066"> <epdcx:valueString>en</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 20: Value as Described Resource
In some cases the resource will not have a URI assigned, or the URI will not be known. Such a resource may still be a value in a statement in one description and the described resource of another description in the same description set.
In such cases, the association between the statement in the first description and the second description is made by using an identifier for the resource which is local to an Eprints-DC-XML instance. This local identifier is used as the value of a epdcx:valueRef XML attribute of one or more Statement Elements and as the value of a 'epdcx:resourceId' XML attribute of a Description Element. Each value of a epdcx:valueRef XML attribute must match the value of a epdcx:resourceId attribute in the same Eprints-DC-XML instance.
Note that this is a syntactic mechanism for linking references to values in statements to the descriptions of those values: the local identifier itself does not appear in the description set.
<?xml version="1.0"?> <epdcx:descriptionSet xmlns:epdcx="http://purl.org/eprint/epdcx/2006-11-16/"> <epdcx:description epdcx:resourceURI="http://eprints.bath.ac.uk/works/12345678/"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/ScholarlyWork" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/title"> <epdcx:valueString>Initial sequencing and analysis of the human genome</epdcx:valueString> </epdcx:statement> <epdcx:statement epdcx:propertyURI="http://purl.org/eprint/terms/isExpressedAs" epdcx:valueRef="expression1" /> <-- reference to value using local identifier --> </epdcx:description> <-- described resource identified by local identifier --> <epdcx:description epdcx:resourceId="expression1"> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/type" epdcx:valueURI="http://purl.org/eprint/entityType/Expression" /> <epdcx:statement epdcx:propertyURI="http://purl.org/dc/elements/1.1/language" epdcx:vesURI="http://purl.org/dc/terms/RFC3066"> <epdcx:valueString>en</epdcx:valueString> </epdcx:statement> </epdcx:description> </epdcx:descriptionSet>
XML Example 21: Value as Described Resource
GRDDL
An XSLT transformation from Eprints-DC-XML to RDF/XML [RDFXML] is available
http://purl.org/eprint/epdcx/xslt/2006-11-16/epdcx2rdfxml.xsl
The GRDDL specification [GRDDL] defines a set of conventions for associating an XML instance document with a transformation.
The transformation will be associated with the set of Eprints-DC-XML instances by providing information about the transformation in a "namespace document"
http://purl.org/eprint/epdcx/2006-11-16/
W3C XML Schema
See also RELAX NG Schema:
Examples
Appendix A. DC-TEXT Representation of Examples
This appendix provides representations of all the examples provided in the main body of the document using the DC-Text syntax [DCTEXT].
(to be completed)
Notes
[1] This document defines one XML format for representing DC metadata description sets in XML. Other formats may exist supporting other subsets of the DCMI Abstract Model. For example, the Open Archives Initiative Protocol for Metadata Harvesting [OAIPMH] defines a format, commonly known as oai_dc, which supports the serialisation only of description sets containing a single description, with statements referencing only the fifteen properties of the DCMES, and using value strings only. oai_dc is a different XML format from Eprints-DC-XML, but that does not change the value and usefulness of oai_dc as a format for serialising that particular subclass of DC metadata description sets.
[2] In this document the term "element" is used to refer only to XML elements, and it should always be interpreted in that sense wherever it occurs. It is not used to refer to the properties of the DCMES.
References
[XML] Extensible Markup Language (XML) 1.0 (Third Edition). W3C Recommendation 04 February 2004. http://www.w3.org/TR/REC-xml
[DCXMLFULL] Expressing Dublin Core metadata using XML (DC-XML-Full). Version 2006-09-18 Working Draft. http://dublincore.org/architecturewiki/DCXMLRevision/DCXMLFGuidelines/2006-09-18
[DCAM] DCMI Abstract Model http://dublincore.org/documents/abstract-model/
[XMLSCHEMA] XML Schema Part 0: Primer Second Edition. W3C Recommendation 28 October 2004. http://www.w3.org/TR/xmlschema-0/
[RFC3986] Uniform Resource Identifier (URI): Generic Syntax http://www.ietf.org/rfc/rfc3986.txt
[RDFXML] RDF/XML Syntax Specification (Revised) W3C Recommendation 10 February 2004. http://www.w3.org/TR/rdf-syntax-grammar/
[GRDDL] Gleaning Resource Descriptions from Dialects of Languages (GRDDL) W3C Working Draft 24 October 2006 http://www.w3.org/TR/2006/WD-grddl-20061024/
[OAIPMH] The Open Archives Initiative Protocol for Metadata Harvesting Protocol Version 2.0 of 2002-06-14. http://www.openarchives.org/OAI/openarchivesprotocol.html
[DCTEXT] DC-Text: A Text Syntax for Dublin Core Metadata Draft of 2006-09-18. http://dublincore.org/architecturewiki/DCText/2006-09-18
