Uses the regular expression (regex()) function for string matching. – Linked Data for Professional Education

Jena Full Text Search

Sun, 13 Aug 2017 08:18:11 +0000

This documentation explains how to configure and use the Full Text extension to Apache Jena's ARQ (the module is included in Fuseki). The extension combines SPARQL and full-text search via Lucene or ElasticSearch (built on Lucene). It gives applications the ability to perform indexed full-text searches within SPARQL queries. Although SPARQL allows the use of regular expressions in FILTER, this is a test on a value retrieved earlier in the query and its use is not indexed. In other words, if you're searching for occurrences of a specific term in the rdfs:label of a bunch of products, then the search will need to examine all selected rdfs:label statements and apply the regular expression to each label in turn. If there are many such statements and many such uses of regex, then it may be appropriate to consider using this extension to take advantage of the performance potential of full text indexing.

URL: http://jena.apache.org/documentation/query/text-query.html
Keywords: SPARQL, REGEX, FILTER, Apache Jena
Publisher: Apache Jena
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P2H
Educational use: professionalDevelopment

Don’t Use a Hammer to Screw in a Nail: Alternatives to REGEX in SPARQL

Sun, 13 Aug 2017 08:18:11 +0000

This brief blog post explains that regular expressions are expensive to evaluate regardless of what language you are using them in. The author suggests that if you can avoid using a regular expression in favor of a simpler string computation, then you can likely get much better performance out of your SPARQL engine. Alternative strategies include using CONTAINS, LCASE, UCASE, STRSTARTS, and STRENDS. If more complex string operations are required, full-text extensions to the SPARQL engine may be an option.

URL: http://www.cray.com/blog/dont-use-hammer-screw-nail-alternatives-regex-sparql/
Keywords: SPARQL, CONTAINS, String operations, REGEX, Jena Text
Author: Vesse, Rob
Publisher: Cray
Date created: 2014-06-03 04:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P10M
Educational use: instruction
Educational audience: student
Interactivity type: expositive

SPARQL and Linked Data Homework Exercises

Sat, 21 Jan 2017 06:46:40 +0000

This document contains several "written" and "electronic" homework questions originally from the course "Semantic Web Topics" at LeHigh University. They include: Write a series of SPARQL queries using a provided schema; Write a SPARQL construct query that generates all triples inferred by a specific RDFS entailment rule; Write a SPARQL construct query to generate
owl:sameAs statements between domains which share specified property; Describe the pros and cons of generating links in the manner specified in the previous question; Using Jena, create a class that can read in all the files in a specified directory and create a Web page that lists a series of publications organized by topic – reading all of the files into a single model and only using SPARQL to retrieve information from the model.

URL: http://www.cse.lehigh.edu/~heflin/courses/sw-2013/hw2.pdf
Keywords: SPARQL, RDF Schema, Entailment regime, Apache Jena, Java
Author: Heflin, Jeff
Date created: 2013-02-01 05:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P4H
Educational use: assessment
Educational audience: teacher-educationSpecialist
Interactivity type: active

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

XQuery/SPARQL Tutorial

Sat, 16 Jan 2016 13:43:28 +0000

This page shows how to access a SPARQL endpoint using an interface provided by Talis. Potentially more valuable, it also provides several dozen example queries, including those covering: Abbreviated query syntax; Aggregate features; Generic queries; and Schema queries.

URL: https://en.wikibooks.org/wiki/XQuery/SPARQL_Tutorial
Keywords: SPARQL, SPARQL endpoint, XQuery, Talis
Publisher: Wikibooks
Date created: 2014-03-26 04:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P1H

0 to 60 on SPARQL queries in 50 minutes

Abi Evans — Thu, 13 Aug 2015 14:33:32 +0000

This links to the PDF version of Ethan Gruber's webinar, which provides an introduction to SPARQL, a query language for RDF. Users will gain hands-on experience crafting queries, starting simply, but evolving in complexity. These queries will focus on coinage data at the SPARQL endpoint hosted by http://nomisma.org with numismatic concepts defined in a SKOS-based thesaurus and physical specimens from three major museum collections linked to these concepts. Results generated from these queries in the form of CSV may be imported directly into Google Fusion Tables for immediate visualization in the form of charts and maps.

URL: https://www.academia.edu/8014017/0_to_60_on_SPARQL_queries_in_50_minutes
Keywords: Geographic queries, SPARQL, Map geolocations
Author: Gruber, Ethan
Date created: 2014-08-01 07:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P60M
Interactivity type: mixed

Introduction to SPARQL

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

A simple (yet thorough) introduction to SPARQL query language based on the W3C documentation. Focuses on aspects of the query language present in SPARQL 1.0 and does not include features added in SPARQL 1.1 Update.

URL: http://www.slideshare.net/szeke/introduction-to-sparql?next_slideshow=2
Keywords: SPARQL, Negation, BIND
Author: Szekely, Pedro
Date created: 2013-05-21 07:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P45M
Educational use: instruction
Educational audience: professional
Interactivity type: expositive

SPARQL Tutorial: Filters

Abi Evans — Thu, 13 Aug 2015 03:26:19 +0000

This brief tutorial discusses how graph matching allows patterns in a graph to be found. This section describes how the values in a solution can be restricted, and covers two such cases (string matching and testing values).

URL: http://jena.apache.org/tutorials/sparql_filters.html
Keywords: Regular expressions, XQuery, SPARQL
Publisher: The Apache Software Foundation
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P10M
Interactivity type: mixed