Z39.50, XML & RDF Applications ZIG Tutorial January 2000 Poul Henrik Jørgensen, Danish Bibliographic Centre,

ZIG Z39.50, XML & RDF / DBC-PHJ 2 Contents Z39.50 Overview Z39.50 and XML Resource Description Framework, RDF Z39.50, XML and RDF Applications

ZIG Z39.50, XML & RDF / DBC-PHJ 3 Web Search Example

ZIG Z39.50, XML & RDF / DBC-PHJ 4 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

ZIG Z39.50, XML & RDF / DBC-PHJ 5 Z39.50 Search Example

ZIG Z39.50, XML & RDF / DBC-PHJ 6 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

ZIG Z39.50, XML & RDF / DBC-PHJ 7 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?

ZIG Z39.50, XML & RDF / DBC-PHJ 8 Z39.50 XML Example

ZIG Z39.50, XML & RDF / DBC-PHJ 9 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

ZIG Z39.50, XML & RDF / DBC-PHJ 10 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)

ZIG Z39.50, XML & RDF / DBC-PHJ 11 RDF Statement The resource (Subject). has the Title (Property) ”Out of Africa” (Value) has the Creator (Property) ”Karen Blixen” (Value)

ZIG Z39.50, XML & RDF / DBC-PHJ 12 RDF Graph Example Karen Blixen Title Out of Africa Creator

ZIG Z39.50, XML & RDF / DBC-PHJ 13 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

ZIG Z39.50, XML & RDF / DBC-PHJ 14 RDF Dublin Core Example Guidance on expressing the Dublin Core within the Resource Description Framework (RDF) Eric Miller Dublin Core; Resource Description Framework; RDF; eXtensible Markup Language; XML text/html en

ZIG Z39.50, XML & RDF / DBC-PHJ 15 RDF XML IFLA 4LM Example

ZIG Z39.50, XML & RDF / DBC-PHJ 16 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.

ZIG Z39.50, XML & RDF / DBC-PHJ 17 RDF Graph Navigation The generic ”Out of Africa” object is expanded to show related works including three translations (some attribute names are in Danish)

ZIG Z39.50, XML & RDF / DBC-PHJ 18 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)