# Presentation: 164518

## Z39.50, XML & RDF  Applications

- ZIG Tutorial January 2000
- Poul Henrik Jørgensen, phj@dbc.dk
- Danish Bibliographic Centre, www.dbc.dk

## Contents

- Z39.50 Overview
- Z39.50 and XML
- Resource Description Framework, RDF
- Z39.50, XML and RDF Applications

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## Web Search Example

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## Z39.50 Overview

- Z39.50 Targets (Z-Servers) supports a standard **system** interface to Z39.50 Origins (Z-Clients)
- Z-Clients support specialised **user** interfaces
- Z-Clients submit **metadata** Searches to Z-Servers
- Z-Servers returns **pointers** to relevant resources
- Z-Servers can return **structured** information according to requests from Z-Clients
- Z-Clients can access different Z-Servers – and vice versa

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## Z39.50 Search Example

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## XML Overview

- HTML was intended to handle **formatted** **text**
- XML is designed by W3C to handle **structured information**
- Programs may access XML structures via the *Document Object Model* (DOM) **Application Program Interface**
- Related standards handle transformations (XSL) and searching of XML structures (XQL)
- XML may transform the Web from a large text archive to a large database of structured information

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## Z39.50 and XML

- Z39.50 handle XML as another transfer syntax like SUTRS, MARC or GRS-1
- XML can do many of the same things as GRS-1- and XML can be edited by hand
- Several Z39.50 Profiles use XML for Metadata, Item Orders, Electronic Document Delivery and Explain Info
- What about Holdings data?

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## Z39.50 XML Example

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## Resource Description Framework

- Describe relationships and attributes of (Internet) resources, i.e. advanced metadata
- Based on *Directed Labelled Graphs* (DLG) and classical Information Analysis
- May be represented by XML – but is basically independent of any representation format.
- Attributes and Relation types may be defined by XML Namespaces, e.g. Dublin Core

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF Elements

- An *RDF Resource* is an instance of one or more *Classes*
- Resources have *Properties* (=attributes)
- A Class may be a *Subclass* of another Class
- Properties are *Values* or *Relations*
*RDF Statements*: Resource (*Subject*) + Property (*Predicate*) + Value (*Object*)

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF Statement

- The resource _[http://doc123](http://doc123/)_ (*Subject*).
- has the Title (*Property*)
- ”Out of Africa” (*Value*)
- has the Creator (Property)
- ”Karen Blixen” (*Value*)

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF Graph Example

- http://doc123

- Karen Blixen

- Title

- Out of Africa

- Creator

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF, IFLA 4LM and DC

- RDF can use any namespace for properties
- Several namespaces can be referenced in a given RDF structure
- Several Z39.50 Profiles use the RDF DC specification for cross-domain access
- DBC use RDF with IFLA Entity-Relationship Model *(IFLA 4LM)* to navigate normative data

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF Dublin Core Example

- <?xml version="1.0"?>
- <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.0/">
- <rdf:Description rdf:about="http://www.ukoln.ac.uk/metadata/resources/dc/datamodel/ WD-dc-rdf/">
- <dc:title> Guidance on expressing the Dublin Core within the Resource Description Framework (RDF) </dc:title>
- <dc:creator> Eric Miller </dc:creator>
- <dc:subject> Dublin Core; Resource Description Framework; RDF; eXtensible Markup Language; XML </dc:subject>
- <dc:format> text/html </dc:format>
- <dc:language> en </dc:language>
- </rdf:Description>
- </rdf:RDF>

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF XML IFLA 4LM Example

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF Graph & IFLA 4LM

- Screen-dumps from the **VisualCat** Client **©Portia I/S**
- A *Person* object has several attributes incl. six names (i.e. synonyms), dates and a title.
- This *Person* is related to an object, with several attributes including *Title* (*”Out of Africa”*)
- Users can click on any object to see related objects as illustrated in the following slide.

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## RDF Graph Navigation

- The generic *”Out of Africa”* object is expanded to show related works including three translations (some attribute names are in Danish)

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19

## Z39.50, XML and RDF Applications

- Z39.50 can support XML as transfer syntax
- Z39.50 can support XQL search language
- Z39.50 can navigate RDF structures
- Z39.50 could support XML Namespaces
- Z39.50 could use HTTP - and possibly Simple Object Access Protocol (SOAP)

- Z39.50, XML & RDF / DBC-PHJ

- ZIG 2000-01-19