SPARQL Programming Language
Introduction to SPARQL Programming Language
SPARQL stands for SPARQL Protocol And RDF Query Language
SPARQL is RDF Querry Language which was developed by W3C in 2008,It can be implemented by C#,Java,C.It allows for query to consist of triple partterns, conjuctions, disjunctions, and optional patterns. It make the web machine-readable. In SPARQL has a tools that allow to connect and semi-automatically construct SQARQL query for a SPARQL endpoint. There is a tool in SQARQL that is used to convert the SQARQL querry to other query language, for example to SQL and to Xquery. Sparql is allow the database to recurite the tripple patterns.
Query form in SQARQL
Queries are used for reading data from the database, in SPARQL language there four different query variations for different purposes.
- SELECT query :Used to extract raw values from a SPARQL endpoint, the results are returned in a table format.
- CONSTRUCT query :Used to extract information from the SPARQL endpoint and transform the results into valid RDF.
- ASK query :Used to provide a simple True/False result for a query on a SPARQL endpoint.
- DESCRIBE query :Used to extract an RDF graph from the SPARQL endpoint, the contents of which is left to the endpoint to decide based on what the maintainer deems as useful information.
The given example will return the names and emails of every person from the database:
{`
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?name ?email
WHERE
{
?person a foaf:Person.
?person foaf:name ?name.
?person foaf:mbox ?email.
}
`}
