The W3C officially unveiled the SPARQL Query Language today via a press release titled: W3C Opens Data on the Web with SPARQL.
A query language for the burgeoning Structured & Linked Data Web (aka Semantic Web / Giant Global Graph). Like SQL, for the Relational Data Model, it provides a query language for the Graph based RDF Data Model.
It's also a REST or SOAP based Web Service that exposes SPARQL access to RDF Data via an endpoint.
In addition, it's also a Query Results Serialization format that includes XML and JSON support.
Why is it Important?
It brings important clarity to the notion of the "Web as a Database" by transforming existing Web Sites, Portals, and Web Services into bona fide corpus of Mesh-able (rather than Mash-able) Data Sources. For instance, you can perform queries that join one or more of the aforementioned data sources in exactly the same manner (albeit different syntax) as you would one or more SQL Tables.
Example:
-- SPARQL equivalent of SQL SELECT * against my personal data space hosted FOAF file
SELECT DISTINCT ?s ?p ?o
FROM <http://myopenlink.net/dataspace/person/kidehen>
WHERE {?s ?p ?o}
-- SPARQL against my social network
-- Note: My SPARQL will be beamed across all of contacts in the social networks of my contacts as long as they are all HTTP URI based within each data space
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT DISTINCT ?Person
FROM <http://myopenlink.net/dataspace/person/kidehen>
WHERE {?s a foaf:Person; foaf:knows ?Person}
Note: you can use the basic SPARQL Endpoint, SPARQL Query By Example, or SPARQL Query Builder Demo tool to experiment with the demonstration queries above.
How Do I use It?
SPARQL is implemented by RDF Data Management Systems (Triple or Quad Stores) just as SQL is implemented by Relational Database Management Systems. The aforementioned data management systems will typically expose SPARQL access via a SPARQL endpoint.
Where are it's implementations?
A SPARQL implementors Testimonial page accompanies the SPARQL press release. In addition the is a growing collection of implementations on the ESW Wiki Page for SPARQL compliant RDF Triple & Quad Stores.
Is this really a big deal?
Yes! SPARQL facilitates an unobtrusive manifestation of a Linked Data Web by way of natural extension of the existing Document Web i.e these Web enclaves co-exist in symbiotic fashion.
As DBpedia very clearly demonstrates, Linked Data makes the Semantic Web demonstrable and much easier to comprehend. Without SPARQL there would be no mechanism for Linked Data deployment, and without Linked Data there is no mechanism for Beaming Queries (directly or indirectly) across the Giant Global Graph of data hosted by Social Networks, Shard Bookmarks Services, Weblogs, Wikis, RSS/Atom/OPML feeds, Photo Galleries and other Web accessible Data Sources (Data Spaces).
Related items
Detailed SPARQL Query Examples using SIOC Data Spaces