Generic handling of metadata/Technology basics

Concept

 * see Generic_handling_of_metadata

Discussion Points

 * exact requirements (known data/unknown data), use cases
 * defining structure, screen config and vocabulary mapping in one file or separated
 * technology decision
 * restrictions on incoming data

Requirements in General

 * view
 * edit
 * search
 * store in repository
 * define metadata
 * define interoperable metadata (resources and statements)= compatibility to RDF, DCAP
 * encoding schemes (controlles vocabulary, syntax restrictions)
 * mapping to Standard vocabulary terms
 * screen configuration
 * label
 * positioning
 * occurence
 * form element
 * validation of data against a schema/DSP
 * additional requirements see known data

Data to handle (Known Data/Unknown Data)

 * Definition (Known data):
 * xml format (only well-formed and valid xml???)
 * schema or DSP is available
 * related concepts: Handling of Semistructured Data might be interesting ???


 * Definition (Unknown data):
 * heterogenous or unstructured data
 * any format
 * no schema od DSP available

RDF/RDFS
RDF Data Model
 * triples consisting of resources (literal or non-literal) and statements/properties
 * subject predicate object. where subject and object are resources, predicate is statement
 * described structure is a directed graph

Syntax/Language
 * Data: variants of rdf triple syntax, xml syntax
 * Schema: RDFS (XML Syntax)

RDF Sample 1: http://example.org/einstein ex:name "Albert Einstein".
 * resources: http://example.org/einstein (non-literal, uri), "Albert Einstein" (literal)
 * statements: ex:name

RDF Sample 2: http://example.org/einstein ex:affiliation http://example.org/mpdl. http://example.org/mpdl ex:name "MPDL".
 * resources: http://example.org/mpdl, http://example.org/einstein, "MPDL"
 * statements: ex:name, ex:affiliation

Rules/Validation
 * RDFS can be extended to Web Ontology Language (OWL)
 * 2 versions of OWL:
 * OWL Lite: definition of classes/subclasses for resources and properties, property range and domain, only cardinality 0 and 1 allowed (occurence)
 * OWL DL: OWL Lite + set operations (intersect, union, complement), unrestricted cardinality, enumeration classes, disjoint classes

XML, XML Schema, Relax NG
Data Model
 * described structure is a ordered tree (graph possible with references)
 * basic components: elements and attributes
 * difference to RDF, DSP: basic components are just syntactical constructs, they don't give any information about the content

Syntax/Language
 * Data: XML
 * Schema: XML Schema, Relax NG, maybe also Schematron

Description Set Profile: DC-DS-XML, DSP
Data Model
 * basic components: resources (or classes), properties and constraints (Vocabulary Encoding Scheme, Syntax Encoding Scheme)

Syntax
 * for Data (Instances): DC-DS-XML, DC-Text Syntax
 * for Definition/Schema: DSP-XML, DSP-RDF , DSP-WIKI , DC-Text Syntax

DSP-XML Sample 1: 

  http://xmlns.com/foaf/0.1/Person  http://example.org/name   

DC-DS-XML Sample 1:     Albert Einstein</dcds:literalValueString> </dcds:statement> </dcds:description> </dcds:descriptionSet>