RDF(S) Tools Adrian Pop, Programming Environments Laboratory Linköping University

November 03,  Introduction  Tool categories  parsers, validators  editors, query tools  databases, crawlers  Editors demos  RDFAuthor, IsaViz, RDFedt, InferEd  Query Tools  Jena RDQL demo  Conclusions

November 03,  Resource Description Framework (RDF)  standard for describing resources on the web  RDF Schema (RDFS)  RDF Vocabulary Description Language  RDF(S) Tools must  read RDF data (parsers/validators)  store RDF data (XML format, triples, or relational/OO DBs)  use RDF data (applications, RSS news, etc)  manipulate RDF data (inference, query, etc)

November 03,  Parsers (Jena, Redland, SWI-Prolog parser)  Validators (W3C RDF Validation service)  Editors (IsaViz, RDFAuthor, RDFEd, InferEd)  Query tools (Jena, etc)  Databases (RSSDB, RDFLib)

November 03,  Jena - A semantic Web Framework for Java   A RDF API  Reading and writing RDF in RDF/XML, N3 and N-Triples  An OWL API  In-memory and persistent storage  RDQL – a query language for RDF  Later on, a RDQL demo

November 03,  Redland RDF Application Framework   A modular, object based library written in C  Java, Perl, PHP, Python, Ruby and Tcl interfaces for manipulating the RDF graph and parts  Parsers and Serializers for reading and writing RDF  Storage for graphs in memory and on disk  Query APIs for the graph by Statement (triples) or by Nodes and Arcs  Statement Streams for construction, parsing, de/serialisation of graphs  Start of query language support.  No memory leaks so far

November 03,  SWI-Prolog parser (Online Demo)  cvsweb/pl/packages/sgml/RDF/online.html?rev= cvsweb/pl/packages/sgml/RDF/online.html?rev=1.11  RDFS explorer, RDF Semantic Extensions   Interesting feature:  provide semantics in Prolog for your properties path(S,O) :- statement(S,path,O). path(X,Z) :- statement(X,path,Y), path(Y,Z).

November 03,  RDF Validation Service   Validating RDF Parser   In general all the RDF parsers do some kind of validation

November 03,  RDFAuthor  RDFAuthor Demo

November 03,  IsaViz  IsaViz Demo

November 03,  RDFedt  RDFedt demo

November 03,  InferEd  products/infered/ products/infered/ InferEd Demo

November 03,  Jena RDQL examples  Queries over the foaf.rdf filefoaf.rdf  Query 1, Select all SELECT * WHERE(?x ?y ?z)  Query 1, Select persons that knows me SELECT ?person, ?knows WHERE(?x ?z), (?x ?person), (?z ?knows)  Go Go

November 03, Storage of RDF graphs  Files  xml format,.n3 format, N-triples format  Databases  relational databases (MySQL, PostgreSQL)  Object-Oriented Databases (ZODB)

November 03,  RDF Tools  are mature enough  become more complex  RDF is more widely used  RSS feeds  Mozilla sidebar, Bookmarks, etc  RDFGateway (application + web + RDF deductive DB)

November 03, Thank you! Questions?

November 03, Resources Ontology Storage and Querying RDF Schema explorer + RDF Semantic Extensions Dave Beckett's Resource Description Framework (RDF) Resource Guide RDFAuthor, RDFAuthor Tutorial Jena - A semantic Web Framework for Java Redland RDF Application Framework RDF Validation Service Validating Parser (VRP), RDF Schema Specific Database (RSSDB), The RDF Query Language (RQL) RDFedt