What is SPARQL endpoint?

What is SPARQL endpoint?

A SPARQL Endpoint is a Point of Presence on an HTTP network that’s capable of receiving and processing SPARQL Protocol requests. It is identified by a URL commonly referred to as a SPARQL Endpoint URL.

What does SPARQL stand for?

SPARQL Protocol and RDF Query Language
SPARQL is a recursive acronym, which stands for SPARQL Protocol and RDF Query Language. SPARQL consists of two parts: query language and protocol. The query part of that is pretty straightforward. SQL is used to query relational data. XQuery is used to query XML data.

How does DBpedia work?

DBpedia extracts factual information from Wikipedia pages, allowing users to find answers to questions where the information is spread across multiple Wikipedia articles. Data is accessed using an SQL-like query language for RDF called SPARQL.

How do you write queries in SPARQL?

A SPARQL query comprises, in order:

1. Prefix declarations, for abbreviating URIs.
2. Dataset definition, stating what RDF graph(s) are being queried.
3. A result clause, identifying what information to return from the query.
4. The query pattern, specifying what to query for in the underlying dataset.

What types of queries does SPARQL support?

SPARQL also supports aggregation, subqueries, negation, creating values by expressions, extensible value testing, and constraining queries by source RDF graph. The results of SPARQL queries can be result sets or RDF graphs.

What types of queries does SPARQL support select all that apply?

In addition to numeric types, SPARQL supports types xsd:string , xsd:boolean and xsd:dateTime (see 11.1 Operand Data Types). 11.3 Operator Mapping lists a set of test functions, including BOUND , isLITERAL and langMATCHES and accessors, including STR , LANG and DATATYPE .

Is DBpedia a knowledge graph?

DBpedia is a crowd-sourced community effort to extract structured content from the information created in various Wikimedia projects. This structured information resembles an open knowledge graph (OKG) which is available for everyone on the Web.

What is the difference between DBpedia and Wikipedia?

DBpedia extracts structured data from the infoboxes in Wikipedia, and publishes them in RDF and a few other formats. Wikidata provide a secondary and tertiary database of structured data that everyone can edit. It does not extract data from Wikipedia, as DBpedia does.

What is prefix in SPARQL?

“PREFIX”, however (without the “@”), is the SPARQL instruction for a declaration of a namespace prefix. It allows you to write prefixed names in queries instead of having to use full URIs everywhere. So it’s a syntax convenience mechanism for shorter, easier to read (and write) queries.

Who invented SPARQL?

There exist tools that allow one to connect and semi-automatically construct a SPARQL query for a SPARQL endpoint, for example ViziQuer….SPARQL.

What kind of query language does SPARQL use?

SPARQL (pronounced sparkle, a recursive acronym for SPARQL Protocol and RDF Query Language) is an RDF query language, that is, a semantic query language for databases, able to retrieve and manipulate data stored in Resource Description Framework (RDF) format.

How many triples are in a SPARQL endpoint?

Collection of dataset created in the context of the W3C Semantic Web Health Care and Life Sciences (HCLS) Interest Group over the past years. Roughly 400 million triples. This endpoint contains data that is also contained in some of the other SPARQL endpoints in this list (such as Neurocommons, LinkedCT, Drugbank etc.).

Which is the Federated form of a SPARQL query?

Federated SPARQL, originally called and still sometimes referred to as SPARQL-FED, is the federated form of a SPARQL Query that provides access to RDF statements/sentences (data) provided by remote SPARQL Query Service endpoints; i.e., this is how SPARQL queries are federated via the SPARQL Protocol.

When did SPARQL become a World Wide Web standard?

It was made a standard by the RDF Data Access Working Group (DAWG) of the World Wide Web Consortium, and is recognized as one of the key technologies of the semantic web. On 15 January 2008, SPARQL 1.0 was acknowledged by W3C as an official recommendation, and SPARQL 1.1 in March, 2013.

https://www.youtube.com/watch?v=w_pJ3XiBWeM