Introduction to RDF & SPARQL
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Basic Querying with SPARQL
Basic Querying with SPARQL Andrew Weidner Metadata Services Coordinator SPARQL SPARQL SPARQL SPARQL SPARQL Protocol SPARQL SPARQL Protocol And SPARQL SPARQL Protocol And RDF SPARQL SPARQL Protocol And RDF Query SPARQL SPARQL Protocol And RDF Query Language SPARQL SPARQL Protocol And RDF Query Language SPARQL Query SPARQL Query Update SPARQL Query Update - Insert triples SPARQL Query Update - Insert triples - Delete triples SPARQL Query Update - Insert triples - Delete triples - Create graphs SPARQL Query Update - Insert triples - Delete triples - Create graphs - Drop graphs Query RDF Triples Query RDF Triples Triple Store Query RDF Triples Triple Store Data Dump Query RDF Triples Triple Store Data Dump Subject – Predicate – Object Query Subject – Predicate – Object ?s ?p ?o Query Dog HasName Cocoa Subject – Predicate – Object ?s ?p ?o Query Cocoa HasPhoto ------- Subject – Predicate – Object ?s ?p ?o Query HasURL http://bit.ly/1GYVyIX Subject – Predicate – Object ?s ?p ?o Query ?s ?p ?o Query SELECT ?s ?p ?o Query SELECT * ?s ?p ?o Query SELECT * WHERE ?s ?p ?o Query SELECT * WHERE { ?s ?p ?o } Query select * WhErE { ?spiderman ?plays ?oboe } http://deathbattle.wikia.com/wiki/Spider-Man http://www.mmimports.com/wp-content/uploads/2014/04/used-oboe.jpg Query SELECT * WHERE { ?s ?p ?o } Query SELECT * WHERE { ?s ?p ?o } Query SELECT * WHERE { ?s ?p ?o } Query SELECT * WHERE { ?s ?p ?o } LIMIT 10 SELECT * WHERE { ?s ?p ?o } LIMIT 10 http://dbpedia.org/snorql SELECT * WHERE { ?s ?p ?o } LIMIT 10 http://dbpedia.org/snorql SELECT * WHERE { ?s -
Semantic Web Core Technologies Semantic Web Core Technologies
12/20/13 Semantic Web Core Technologies Semantic Web Core Technologies Muhammad Alsharif, mhalsharif at gmail.com (A paper written under the guidance of Prof. Raj Jain) Download Abstract This is survey of semantic web primary infrastructure. Semantic web aims to link the data everywhere and make them understandable for machines as well as humans. Implementing the full vision of the semantic web has a long way to go but a number of its necessary building blocks are being standardized. In this paper, the three core technologies for linking web data, defining vocabularies, and querying information are going to be introduced and discussed. Keywords: web 3.0, semantic web, semantic web stack, resource description framework, RDF schema, web ontology language, SPARQL Table of Contents 1. Introduction 2. Semantic Web Stack 3. Linked Data 3.1. Resource Description Framework (RDF) 3.2. RDF vs XML 4. Vocabularies 4.1. RDFS 4.2. RDFS vs OWL 5. Query 5.1. SPARQL 5.2. SPARQL vs SQL 6. Summary 7. Acronyms 8. References 1. Introduction The main goal of the semantic web is to improve upon the existing “web of documents†to be a “web of dataâ€. The first version of the web (web 1.0) revolutionized the use of Internet in both academia and industry by introducing the idea of hyperlinking, which has interconnected billions of web pages over the globe and made documents accessible from multiple points. Web 2.0 has expanded over this concept by adding the user interactivity/participation element such as the dynamic creation of data on websites by content management systems (CMS) which has led to the emergence of social media such as blogs, flickr, youtube, twitter, etc. -
Mapping Spatiotemporal Data to RDF: a SPARQL Endpoint for Brussels
International Journal of Geo-Information Article Mapping Spatiotemporal Data to RDF: A SPARQL Endpoint for Brussels Alejandro Vaisman 1, * and Kevin Chentout 2 1 Instituto Tecnológico de Buenos Aires, Buenos Aires 1424, Argentina 2 Sopra Banking Software, Avenue de Tevuren 226, B-1150 Brussels, Belgium * Correspondence: [email protected]; Tel.: +54-11-3457-4864 Received: 20 June 2019; Accepted: 7 August 2019; Published: 10 August 2019 Abstract: This paper describes how a platform for publishing and querying linked open data for the Brussels Capital region in Belgium is built. Data are provided as relational tables or XML documents and are mapped into the RDF data model using R2RML, a standard language that allows defining customized mappings from relational databases to RDF datasets. In this work, data are spatiotemporal in nature; therefore, R2RML must be adapted to allow producing spatiotemporal Linked Open Data.Data generated in this way are used to populate a SPARQL endpoint, where queries are submitted and the result can be displayed on a map. This endpoint is implemented using Strabon, a spatiotemporal RDF triple store built by extending the RDF store Sesame. The first part of the paper describes how R2RML is adapted to allow producing spatial RDF data and to support XML data sources. These techniques are then used to map data about cultural events and public transport in Brussels into RDF. Spatial data are stored in the form of stRDF triples, the format required by Strabon. In addition, the endpoint is enriched with external data obtained from the Linked Open Data Cloud, from sites like DBpedia, Geonames, and LinkedGeoData, to provide context for analysis. -
Validating RDF Data Using Shapes
83 Validating RDF data using Shapes a Jose Emilio Labra Gayo a University of Oviedo, Spain Abstract RDF forms the keystone of the Semantic Web as it enables a simple and powerful knowledge representation graph based data model that can also facilitate integration between heterogeneous sources of information. RDF based applications are usually accompanied with SPARQL stores which enable to efficiently manage and query RDF data. In spite of its well known benefits, the adoption of RDF in practice by web programmers is still lacking and SPARQL stores are usually deployed without proper documentation and quality assurance. However, the producers of RDF data usually know the implicit schema of the data they are generating, but they don't do it traditionally. In the last years, two technologies have been developed to describe and validate RDF content using the term shape: Shape Expressions (ShEx) and Shapes Constraint Language (SHACL). We will present a motivation for their appearance and compare them, as well as some applications and tools that have been developed. Keywords RDF, ShEx, SHACL, Validating, Data quality, Semantic web 1. Introduction In the tutorial we will present an overview of both RDF is a flexible knowledge and describe some challenges and future work [4] representation language based of graphs which has been successfully adopted in semantic web 2. Acknowledgements applications. In this tutorial we will describe two languages that have recently been proposed for This work has been partially funded by the RDF validation: Shape Expressions (ShEx) and Spanish Ministry of Economy, Industry and Shapes Constraint Language (SHACL).ShEx was Competitiveness, project: TIN2017-88877-R proposed as a concise and intuitive language for describing RDF data in 2014 [1]. -
Semantics Developer's Guide
MarkLogic Server Semantic Graph Developer’s Guide 2 MarkLogic 10 May, 2019 Last Revised: 10.0-8, October, 2021 Copyright © 2021 MarkLogic Corporation. All rights reserved. MarkLogic Server MarkLogic 10—May, 2019 Semantic Graph Developer’s Guide—Page 2 MarkLogic Server Table of Contents Table of Contents Semantic Graph Developer’s Guide 1.0 Introduction to Semantic Graphs in MarkLogic ..........................................11 1.1 Terminology ..........................................................................................................12 1.2 Linked Open Data .................................................................................................13 1.3 RDF Implementation in MarkLogic .....................................................................14 1.3.1 Using RDF in MarkLogic .........................................................................15 1.3.1.1 Storing RDF Triples in MarkLogic ...........................................17 1.3.1.2 Querying Triples .......................................................................18 1.3.2 RDF Data Model .......................................................................................20 1.3.3 Blank Node Identifiers ..............................................................................21 1.3.4 RDF Datatypes ..........................................................................................21 1.3.5 IRIs and Prefixes .......................................................................................22 1.3.5.1 IRIs ............................................................................................22 -
PDF Formats; the XHTML Version Has Active Links That You Can Follow
Semantic Web @ W3C: Activities, Recommendations and State of Adoption Athens, GA, USA, 2006-11-09 Ivan Herman, W3C Ivan Herman, W3C RDF(S), tools We have a solid specification since 2004: well defined (formal) semantics, clear RDF/XML syntax Lots of tools are available. Are listed on W3C’s wiki: RDF programming environment for 14+ languages, including C, C++, Python, Java, Javascript, Ruby, PHP,… (no Cobol or Ada yet ) 13+ Triple Stores, ie, database systems to store datasets 16+ general development tools (specialized editors, application builders, …) etc Ivan Herman, W3C RDF(S), tools (cont.) Note the large number of large corporations among the tool developers: Adobe, IBM, Software AG, Oracle, HP, Northrop Grumman, … …but the small companies and independent developers also play a major role! Some of the tools are Open Source, some are not; some are very mature, some are not : it is the usual picture of software tools, nothing special any more! Anybody can start developing RDF-based applications today Ivan Herman, W3C RDF(S), tools (cont.) There are lots of tutorials, overviews, or books around the wiki page on books lists 20+ (English) textbooks; 19+ proceedings for 2005 & 2006 alone… again, some of them good, some of them bad, just as with any other areas… Active developers’ communities Ivan Herman, W3C Large datasets are accumulating IngentaConnect bibliographic metadata storage: over 200 million triplets UniProt Protein Database: 262 million triplets RDF version of Wikipedia: more than 47 million triplets RDFS/OWL Representation -
Computational Integrity for Outsourced Execution of SPARQL Queries
Computational integrity for outsourced execution of SPARQL queries Serge Morel Student number: 01407289 Supervisors: Prof. dr. ir. Ruben Verborgh, Dr. ir. Miel Vander Sande Counsellors: Ir. Ruben Taelman, Joachim Van Herwegen Master's dissertation submitted in order to obtain the academic degree of Master of Science in Computer Science Engineering Academic year 2018-2019 Computational integrity for outsourced execution of SPARQL queries Serge Morel Student number: 01407289 Supervisors: Prof. dr. ir. Ruben Verborgh, Dr. ir. Miel Vander Sande Counsellors: Ir. Ruben Taelman, Joachim Van Herwegen Master's dissertation submitted in order to obtain the academic degree of Master of Science in Computer Science Engineering Academic year 2018-2019 iii c Ghent University The author(s) gives (give) permission to make this master dissertation available for consultation and to copy parts of this master dissertation for personal use. In the case of any other use, the copyright terms have to be respected, in particular with regard to the obligation to state expressly the source when quoting results from this master dissertation. August 16, 2019 Acknowledgements The topic of this thesis concerns a rather novel and academic concept. Its research area has incredibly talented people working on a very promising technology. Understanding the core principles behind proof systems proved to be quite difficult, but I am strongly convinced that it is a thing of the future. Just like the often highly-praised artificial intelligence technology, I feel that verifiable computation will become very useful in the future. I would like to thank Joachim Van Herwegen and Ruben Taelman for steering me in the right direction and reviewing my work quickly and intensively. -
Rdfa in XHTML: Syntax and Processing Rdfa in XHTML: Syntax and Processing
RDFa in XHTML: Syntax and Processing RDFa in XHTML: Syntax and Processing RDFa in XHTML: Syntax and Processing A collection of attributes and processing rules for extending XHTML to support RDF W3C Recommendation 14 October 2008 This version: http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014 Latest version: http://www.w3.org/TR/rdfa-syntax Previous version: http://www.w3.org/TR/2008/PR-rdfa-syntax-20080904 Diff from previous version: rdfa-syntax-diff.html Editors: Ben Adida, Creative Commons [email protected] Mark Birbeck, webBackplane [email protected] Shane McCarron, Applied Testing and Technology, Inc. [email protected] Steven Pemberton, CWI Please refer to the errata for this document, which may include some normative corrections. This document is also available in these non-normative formats: PostScript version, PDF version, ZIP archive, and Gzip’d TAR archive. The English version of this specification is the only normative version. Non-normative translations may also be available. Copyright © 2007-2008 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply. Abstract The current Web is primarily made up of an enormous number of documents that have been created using HTML. These documents contain significant amounts of structured data, which is largely unavailable to tools and applications. When publishers can express this data more completely, and when tools can read it, a new world of user functionality becomes available, letting users transfer structured data between applications and web sites, and allowing browsing applications to improve the user experience: an event on a web page can be directly imported - 1 - How to Read this Document RDFa in XHTML: Syntax and Processing into a user’s desktop calendar; a license on a document can be detected so that users can be informed of their rights automatically; a photo’s creator, camera setting information, resolution, location and topic can be published as easily as the original photo itself, enabling structured search and sharing. -
RDF Query Languages Need Support for Graph Properties
RDF Query Languages Need Support for Graph Properties Renzo Angles1, Claudio Gutierrez1, and Jonathan Hayes1,2 1 Dept. of Computer Science, Universidad de Chile 2 Dept. of Computer Science, Technische Universit¨at Darmstadt, Germany {rangles,cgutierr,jhayes}@dcc.uchile.cl Abstract. This short paper discusses the need to include into RDF query languages the ability to directly query graph properties from RDF data. We study the support that current RDF query languages give to these features, to conclude that they are currently not supported. We propose a set of basic graph properties that should be added to RDF query languages and provide evidence for this view. 1 Introduction One of the main features of the Resource Description Framework (RDF) is its ability to interconnect information resources, resulting in a graph-like structure for which connectivity is a central notion [GLMB98]. As we will argue, basic concepts of graph theory such as degree, path, and diameter play an important role for applications that involve RDF querying. Considering the fact that the data model influences the set of operations that should be provided by a query language [HBEV04], it follows the need for graph operations support in RDF query languages. For example, the query “all relatives of degree 1 of Alice”, submitted to a genealogy database, amounts to retrieving the nodes adjacent to a resource. The query “are suspects A and B related?”, submitted to a police database, asks for any path connecting these resources in the (RDF) graph that is stored in this database. The query “what is the Erd˝osnumber of Alberto Mendelzon”, submitted to (a RDF version of) DBLP, asks simply for the length of the shortest path between the nodes representing Erd˝osand Mendelzon. -
Using Shape Expressions (Shex) to Share RDF Data Models and to Guide Curation with Rigorous Validation B Katherine Thornton1( ), Harold Solbrig2, Gregory S
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Repositorio Institucional de la Universidad de Oviedo Using Shape Expressions (ShEx) to Share RDF Data Models and to Guide Curation with Rigorous Validation B Katherine Thornton1( ), Harold Solbrig2, Gregory S. Stupp3, Jose Emilio Labra Gayo4, Daniel Mietchen5, Eric Prud’hommeaux6, and Andra Waagmeester7 1 Yale University, New Haven, CT, USA [email protected] 2 Johns Hopkins University, Baltimore, MD, USA [email protected] 3 The Scripps Research Institute, San Diego, CA, USA [email protected] 4 University of Oviedo, Oviedo, Spain [email protected] 5 Data Science Institute, University of Virginia, Charlottesville, VA, USA [email protected] 6 World Wide Web Consortium (W3C), MIT, Cambridge, MA, USA [email protected] 7 Micelio, Antwerpen, Belgium [email protected] Abstract. We discuss Shape Expressions (ShEx), a concise, formal, modeling and validation language for RDF structures. For instance, a Shape Expression could prescribe that subjects in a given RDF graph that fall into the shape “Paper” are expected to have a section called “Abstract”, and any ShEx implementation can confirm whether that is indeed the case for all such subjects within a given graph or subgraph. There are currently five actively maintained ShEx implementations. We discuss how we use the JavaScript, Scala and Python implementa- tions in RDF data validation workflows in distinct, applied contexts. We present examples of how ShEx can be used to model and validate data from two different sources, the domain-specific Fast Healthcare Interop- erability Resources (FHIR) and the domain-generic Wikidata knowledge base, which is the linked database built and maintained by the Wikimedia Foundation as a sister project to Wikipedia. -
Enhancing JSON to RDF Data Conversion with Entity Type Recognition
Enhancing JSON to RDF Data Conversion with Entity Type Recognition Fellipe Freire, Crishane Freire and Damires Souza Academic Unit of Informatics, Federal Institute of Education, Science and Technology of Paraiba, João Pessoa, Brazil Keywords: RDF Data Conversion, Entity Type Recognition, Semi-Structured Data, JSON Documents, Semantics Usage. Abstract: Nowadays, many Web data sources and APIs make their data available on the Web in semi-structured formats such as JSON. However, JSON data cannot be directly used in the Web of data, where principles such as URIs and semantically named links are essential. Thus it is necessary to convert JSON data into RDF data. To this end, we have to consider semantics in order to provide data reference according to domain vocabularies. To help matters, we present an approach which identifies JSON metadata, aligns them with domain vocabulary terms and converts data into RDF. In addition, along with the data conversion process, we provide the identification of the semantically most appropriate entity types to the JSON objects. We present the definitions underlying our approach and results obtained with the evaluation. 1 INTRODUCTION principles of this work is using semantics provided by the knowledge domain of the data to enhance The Web has evolved into an interactive information their conversion to RDF data. To this end, we use network, allowing users and applications to share recommended open vocabularies which are data on a massive scale. To help matters, the Linked composed by a set of terms, i.e., classes and Data principles define a set of practices for properties useful to describe specific types of things publishing structured data on the Web aiming to (LOV Documentation, 2016). -
An Introduction to RDF
An Introduction to RDF Knowledge Technologies 1 Manolis Koubarakis Acknowledgement • This presentation is based on the excellent RDF primer by the W3C available at http://www.w3.org/TR/rdf-primer/ and http://www.w3.org/2007/02/turtle/primer/ . • Much of the material in this presentation is verbatim from the above Web site. Knowledge Technologies 2 Manolis Koubarakis Presentation Outline • Basic concepts of RDF • Serialization of RDF graphs: XML/RDF and Turtle • Other Features of RDF (Containers, Collections and Reification). Knowledge Technologies 3 Manolis Koubarakis What is RDF? •TheResource Description Framework (RDF) is a data model for representing information (especially metadata) about resources in the Web. • RDF can also be used to represent information about things that can be identified on the Web, even when they cannot be directly retrieved on the Web (e.g., a book or a person). • RDF is intended for situations in which information about Web resources needs to be processed by applications, rather than being only displayed to people. Knowledge Technologies 4 Manolis Koubarakis Some History • RDF draws upon ideas from knowledge representation, artificial intelligence, and data management, including: – Semantic networks –Frames – Conceptual graphs – Logic-based knowledge representation – Relational databases • Shameless self-promotion : The closest to RDF, pre-Web knowledge representation language is Telos: John Mylopoulos, Alexander Borgida, Matthias Jarke, Manolis Koubarakis: Telos: Representing Knowledge About Information Systems. ACM Trans. Inf. Syst. 8(4): 325-362 (1990). Knowledge Technologies 5 Manolis Koubarakis The Semantic Web “Layer Cake” Knowledge Technologies 6 Manolis Koubarakis RDF Basics • RDF is based on the idea of identifying resources using Web identifiers and describing resources in terms of simple properties and property values.