1.1/ March 21, 2013; 6 years ago ( 2013-03-21)WebsiteMajor,SPARQL (pronounced ', a for SPARQL Protocol and RDF Query Language) is an —that is, a for —able to retrieve and manipulate data stored in format. It was made a standard by the RDF Data Access Working Group (DAWG) of the, and is recognized as one of the key technologies of the. On 15 January 2008, SPARQL 1.0 became an official W3C Recommendation, and SPARQL 1.1 in March, 2013.SPARQL allows for a query to consist of, and optional.Implementations for multiple exist.
There exist tools that allow one to connect and semi-automatically construct a SPARQL query for a SPARQL endpoint, for example ViziQuer.In addition, there exist tools that translate SPARQL queries to other query languages, for example to and to. Contents.Advantages SPARQL allows users to write queries against what can loosely be called 'key-value' data or, more specifically, data that follow the specification of the. Thus, the entire database is a set of 'subject-predicate-object' triples.
This is analogous to some databases' usage of the term 'document-key-value', such as.In terms, data can also be considered a table with three columns – the subject column, the predicate column, and the object column. The subject in RDF is analogous to an entity in a SQL database, where the data elements (or fields) for a given business object are placed in multiple columns, sometimes spread across more than one table, and identified by a.
In RDF, those fields are instead represented as separate predicate/object rows sharing the same subject, often the same unique key, with the predicate being analogous to the column name and the object the actual data. Unlike relational databases, the object column is heterogeneous: the per-cell data type is usually implied (or specified in the ) by the value. Also unlike SQL, RDF can have multiple entries per predicate; for instance, one could have multiple 'child' entries for a single 'person', and can return collections of such objects, like 'children'.Thus, SPARQL provides a full set of analytic query operations such as JOIN, SORT, AGGREGATE for data whose is intrinsically part of the data rather than requiring a separate schema definition. However, schema information (the ontology) is often provided externally, to allow joining of different datasets unambiguously. In addition, SPARQL provides specific traversal syntax for data that can be thought of as a graph.The example below demonstrates a simple query that leverages the ontology definition ('friend of a friend').Specifically, the following query returns names and emails of every person in the dataset. ^ Hebeler, John; Fisher, Matthew; Blace, Ryan; Perez-Lopez, Andrew (2009). Semantic Web Programming.
SPARQL, the subject of this tutorial, is the standard tool for extracting data from RDF graphs. Consider a graph, G. G contains triples that share objects or subjects (using Turtle syntax, the: prefix is assumed to be defined for all subsequent examples). If you type a name into the text box next that button (like query1).
Indianapolis, Indiana:. P. 406. Beckett, Dave (6 October 2011). [email protected].
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Jim Rapoza (2 May 2006). Retrieved 17 January 2007. Segaran, Toby; Evans, Colin; Taylor, Jamie (2009). Programming the Semantic Web. O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. 15 January 2008. Retrieved 1 October 2009.
(PDF). 4 February 2012. Retrieved 27 November 2013. 21 March 2013.
Retrieved 25 April 2013. 6 October 2006. Retrieved 17 January 2007. Retrieved 1 October 2009.
Retrieved 25 February 2011. Retrieved 4 February 2012.
Retrieved 4 February 2012.External links Wikimedia Commons has media related to., was RDF Data Access Working Group. (legacy). (legacy). (legacy). Mappings between OWL-RDF/S & XML Schemas, and XML Schema to OWL Transformation.
This content is part of the series: Data integration at scaleStay tuned for additional content in this series.In ',' you learned about the Resource Description Framework: a World Wide Web Consortium (W3C) standard defining a graph-based model that allows for completely portable, flexible data from virtually limitless sources. The ability to connect data at scale is powerful, but at some point, you'll also want to ask questions of RDF data. That task requires a query language that understands the RDF graph structure and network-based identifiers.No standardized means to query RDF data was availableuntil long after the RDF model came into being. A half dozen or more proprietary query languages were used, each with its own peculiarities and incompatibilities. That situation undercut the vision of portable data by not allowing common queries to work against different RDF storage systems.
Fortunately, in 2008, the W3C released the recursively named (SPARQL). By using a SPARQL client, users can execute queries locally by pulling the data to them, or remotely through the SPARQL Protocol by pushing queries to the server.
You can use the same query syntax on your own data or someone else's. Related topics.: Read the SPARQL-related specifications.: Work through some SPARQL tutorials., 2d ed. (Bob DuCharme, O'Reilly Media, 2013): Read the leading book on SPARQL.: Read about a less burdensome way of allowing clients to query information remotely.: Stardog is a graph database that supports theSemantic Web standards, SPARQL queries, and the SPARQL Protocol.: Virtuoso is a hybrid database that supports the Semantic Web standards, SPARQL queries, and the SPARQL Protocol.: AllegroGraph is a graph database that supports the Semantic Web standards, SPARQL queries, and the SPARQL Protocol.
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