SPARQL

From GetSemantic

SPARQL is a common query language for RDF documents and data sources, and is also a HTTP-POST-based protocol for sending queries to SPARQL Endpoints. There is also a defined XML representation for results but results may be delivered in other formats including JSON and native language objects (arrays in PHP, for instance, or dictionary/list combinations in Python).

There are four key commands in SPARQL:

SELECT - selects results from a graph, similarly to a SQL SELECT query
CONSTRUCT - construct an RDF document from a graph based on certain results
DESCRIBE - return information about one subject
ASK - returns a boolean (true or false) depending on whether results are found or not