XML Schema for DC Libraries AP DC Libraries

XML Schema for DC Libraries AP DC Libraries WG Meeting, DC-2005, Madrid, Spain, Tuesday 13 September 2005 Pete Johnston Research Officer, UKOLN, University of Bath UKOLN is supported by: www. bath. ac. uk A centre of expertise in digital information management www. ukoln. ac. uk

XML Schema for DC Libraries AP • • • XML Schema DCMI Abstract Model XML Binding for DC Application Profiles XML Schema for DC Lib AP A centre of expertise in digital information management www. ukoln. ac. uk

XML Schema • XML Schema describes structure of class of XML documents – names of XML elements/attributes – constraints on XML element content/attribute values – datatyping for XML element content/attribute values • XML "instance document" • Schema validation A centre of expertise in digital information management www. ukoln. ac. uk

XML Schemas for DC Lib AP • So – what should be the structure of this class of XML documents? – what XML elements/attributes? – what content models? – what datatypes? – etc etc • What is this XML Schema for? A centre of expertise in digital information management www. ukoln. ac. uk

Dublin Core is not an XML format <? xml version="1. 0" encoding="UTF-8"? > <my: DC xmlns: dc="http: //purl. org/dc/elements/1. 1/" xmlns: dcterms="http: //purl. org/dc/terms/" xmlns: my="http: //purl. org/my/" xmlns: xsd="http: //www. w 3. org/2001/XMLSchema" > <dc: title xml: lang="en">My Thing</dc: title> <dc: description xml: lang="en">My thing is a thingummy. </dc: description> <dcterms: created>2005 -03 -15</dcterms: created> </my: DC>

Dublin Core is. . . • a vocabulary/set of terms. . . – managed by DCMI (Usage Board) – defined and used within. . . • a conceptual model/framework/set of rules. . . – – DCMI Abstract Model describes how to use these (and other) terms. . . to make statements. . . that form descriptions (of resources) A centre of expertise in digital information management www. ukoln. ac. uk

Description Set Description Resource URI Statement Property URI Value URI Vocab Enc Scheme URI Property URI Value string Syntx Enc Scheme URI Property URI Rich representation Property URI Value string

DCMI Abstract Model and Bindings • DCAM conceptual model – types of construct – relationships between constructs • Description sets encoded as records • Binding specification – mapping between constructs in conceptual model to components in syntax • Two way – encoding application: description set -> record – decoding application: record -> description set A centre of expertise in digital information management www. ukoln. ac. uk

DCMI Abstract Model and XML • DCMI provides multiple "encoding guidelines" specifications – XHTML, RDF (Simple, Qualified), XML • Guidelines for implementing Dublin Core in XML (2003) – XML binding for DC metadata • Other non-DCMI XML bindings for DC deployed • Mapping between constructs in conceptual model to components in XML – XML elements (names, content), – XML attributes (values) – models actually different from DCAM (DC Arch WG) A centre of expertise in digital information management www. ukoln. ac. uk

DC Application Profile • Specifies terms used in a class of description sets – Information on how properties applied in context of application – Constraints on occurrence of statements – Constraints on values (vocabulary encoding schemes) – Constraints on value representations • value URI • value string/syntax encoding scheme • rich representation A centre of expertise in digital information management www. ukoln. ac. uk

XML Schemas for DC Lib AP • XML Schema for DC Lib AP should describes structure of the class of XML documents that are serialisations of DC Lib AP metadata descriptions, created according to DC-XML 2003 binding A centre of expertise in digital information management www. ukoln. ac. uk

XML Schemas for DC Lib AP • Schema for "dclib" XML Namespace – temporary URI for XML Namespace Name – temporary schema. Location – imports DCMI schemas for "dc", "dcterms" XML Namespaces – imports Lo. C schema for "mods" XML Namespace (v 3. 0) – declare XML element (dclib: descriptions) to represent DCAM description set – declare XML element (dclib: description) to represent DCAM description A centre of expertise in digital information management www. ukoln. ac. uk

XML Schemas for DC Lib AP • Content model for dclib: description references XML elements representing statements – use of substitution groups in DCMI XML Schemas means that reference to property makes all subproperties available • Use of XML Schema datatyping in DCMI XML Schemas means can't limit encoding schemes used for property • XML Schema: Occurrence/obligation requires ordering A centre of expertise in digital information management www. ukoln. ac. uk

XML Schemas for DC Lib AP • References to XML element declarations in Lo. C "mods" schema introduces content models from MODS XML format – mods: location (sub-elements mods: url, mods: physical. Location) – mods: origin. Info (sub-elements mods: edition, mods: date. Captured) • Problem: – XML sub-tree constructed according to rules of MODS XML format – XML sub-tree has no interpretation in DC XML binding • XML fragments conforming to different XML formats can not generally be merged in this way A centre of expertise in digital information management www. ukoln. ac. uk

DC and MODS • MODS-XML is binding for MODS; DC-XML is binding for DCAM (almost!) • MODS based on hierarchical data model; DCAM based on statement model • MODS "elements" are "containers"; DC "elements" are properties, types of relationship • MODS "elements" have attributes; DC "elements" do not • MODS "elements" interpreted in context of hierarchy; DC "elements" interpreted in context of DCAM A centre of expertise in digital information management www. ukoln. ac. uk

DC and MODS • Need to qualify notion of "element reuse", "mix & match" • "Terms" referenced in DC metadata descriptions are instances of concepts in DCAM, so. . . –. . . "terms" referenced in DCAPs must be too – MODS elements are not • Need to create new terms which are appropriate for use in DC metadata descriptions – Analyse information conveyed by MODS constructs – Create properties, vocab encoding schemes etc to represent that information – Assign URIs to those properties, etc A centre of expertise in digital information management www. ukoln. ac. uk

XML Schema for DC Libraries AP DC Libraries WG Meeting, DC-2005, Madrid, Spain, Tuesday 13 September 2005 Pete Johnston Research Officer, UKOLN, University of Bath UKOLN is supported by: www. bath. ac. uk A centre of expertise in digital information management www. ukoln. ac. uk