Uses OPTIONAL to formulate queries to return the values of optional variables when available. – Linked Data for Professional Education

SPARQL: Using Operators Tutorial and Quiz

Thu, 24 Nov 2016 05:51:17 +0000

This slide tutorial focuses on using various operators in SPARQL queries. Several examples are provided which include the RDF data being queried, the SPARQL query itself, and the result table. This is followed by quiz questions which ask the user to query DBpedia's SPARQL endpoint. The answers to the question (in the form of completed SPARQL queries) are included.

URL: http://skkudatalab.weebly.com/sparql-operators.html
Keywords: DBpedia, SPARQL
Author: Oh, Sam
Publisher: Sungkyunkwan University (SKKU)
Date created: 2016-11-22 05:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P40M
Educational use: instruction
Educational audience: professional
Interactivity type: expositive

Example SPARQL queries

Sat, 16 Jan 2016 13:43:29 +0000

This page, which contains SPARQL tools, tips, sample queries, is just starting out and the authors hope it can become a resource for useful snippets of information shared among members of the community. There is also a "Tools" page in Sourceforge that lists more substantial contributions and extensions to VIVO. This page also contains an example of a JSON result and a JavaScript example of how to run a SPARQL query and get back JSON.

URL: https://wiki.duraspace.org/display/VIVO/Example+SPARQL+queries
Keywords: JavaScript, JSON, VIVO, SPARQL
Author: Conlon, Mike
Publisher: Duraspace
Date created: 2016-08-24 04:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng

SPARQL Queries for Publications and Authors

Sat, 16 Jan 2016 13:43:29 +0000

This page contains SPARQL queries useful for finding information on authors and publications on VIVO. These query examples, if adapted, have other useful applications as well.

URL: https://wiki.duraspace.org/display/VIVO/SPARQL+Queries+for+Publications+and+Authors
Keywords: SPARQL, VIVO
Author: Rejack, Nicholas
Publisher: Duraspace
Date created: 2014-04-02 04:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P10M
Educational use: professionalDevelopment
Educational audience: professional
Interactivity type: mixed

On the Semantics of SPARQL Queries with Optional Matching under Entailment Regimes

Sat, 16 Jan 2016 13:43:29 +0000

This presentation covers the semantics of SPARQL queries with optional matching features under entailment regimes. It argues that normative semantics may lead to answers that are in conflict with the intuitive meaning of optional matching, where unbound variables naturally represent unknown information. The presenters propose an extension of the SPARQL algebra that addresses these issues and is compatible with any entailment regime satisfying the minimal requirements given in the normative specification. They argue that this solution comes at no cost for regimes with an entailment relation of reasonable complexity and that it preserves the known properties of optional matching that are commonly exploited for static analysis and optimization.

URL: http://videolectures.net/iswc2014_kostylev_sparql_queries/
Keywords: Entailment regimes, Unbound variable, Normative semantics, Web Ontology Language (OWL), Strict semantics
Author: Kostylev, Egor
Date created: 2014-12-19 05:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P15M

Towards Reconciling SPARQL and Certain Answers

Abi Evans — Tue, 15 Sep 2015 02:33:08 +0000

SPARQL entailment regimes are strongly influenced by the big body of works on ontology-based query answering, notably in the area of Description Logics (DLs). However, the semantics of query answering under SPARQL entailment regimes is defined in a more naive and much less expressive way than the certain answer semantics usually adopted in DLs. The goal of this work is to introduce an
intuitive certain answer semantics for SPARQL and to show the feasibility of this approach. It shows that the complexity of the most fundamental query analysis tasks (such as query containment and equivalence testing) is not
negatively affected by the presence of OWL 2 QL entailment under
the proposed semantics.

URL: http://www.simkus.info/wp-content/uploads/2014/10/sparql-certain.pdf
Keywords: Web Ontology Language (OWL), SPARQL, Description Logics, Query rewriting, Basic Graph Pattern (BGP)
Author: Fischl, Wolfgang
Publisher: Pichler, Reinhard
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P30M
Educational use: instruction
Educational audience: teacher-educationSpecialist
Interactivity type: expositive

SPARQL Tutorial: Optional Information

Abi Evans — Thu, 13 Aug 2015 03:26:20 +0000

This brief tutorial emphasizes that RDF is semi-structured data, which means that SPARQL has the ability to query for data but will fail when that data does not exist. That is, unless one uses an optional part to extend the information found in a query solution but to return the non-optional information anyway. Also discusses using OPTIONALS with FILTERS, and using caution when using the same variable in two or more OPTIONALS clauses.

URL: http://jena.apache.org/tutorials/sparql_optionals.html
Keywords: SPARQL, BIND
Publisher: The Apache Software Foundation
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P10M
Educational use: instruction
Educational audience: professional
Interactivity type: mixed

SPARQL Tutorial: Alternatives in a Pattern

Abi Evans — Thu, 13 Aug 2015 03:26:20 +0000

This brief tutorial shows that another way of dealing with the semi-structured nature of RDF data is to query for one of a number of possibilities. This section covers UNION patterns, where one of a number of possibilities is tried.

URL: http://jena.apache.org/tutorials/sparql_union.html
Keywords: SPARQL
Publisher: The Apache Software Foundation
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P10M
Educational audience: student
Interactivity type: mixed

Simple SPARQL Tutorial: SPARQL query … the OPTIONAL Graph Pattern

Abi Evans — Thu, 13 Aug 2015 03:26:18 +0000

Tutorial showing how to modify a query to return instances of data that may or may not exist- the OPTIONAL Graph Pattern.

URL: https://www.youtube.com/watch?v=Bu24sfQcyow
Keywords: SPARQL
Author: Sadawi, Noureddin
Date created: 2014-03-03 07:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P10M