RDF Query

An RDF query is a question that you ask an RDF program that knows how to navigate RDF data.

See Also RDFQuery/Ideas

Implementations of RDF Query

• What RDF query Implementations are available?
  • see FAQ section of SWAD-Europe: Databases, Query, API, Interfaces report on Query languages, EswWp7
  • see DawgShows, SparqlImplementations
• Are there, or will there be, W3C working groups dedicated to RDF queries?
  • yes: RDF Data Access Working Group
• Does RDF query relate to XML query? If so, how?
• Which RDF query languages can handle DAML+oil/OWL properties like inverse, unambiguousProperty?
• How does RDF query handle datatypes?
• Which query languages for RDF allow you to specify optional variables to bind?
• Which RDF query languages are widely deployed?

Definitions

• What is an RDF query?
• How do you query a reified statement? (see RdfReification)
• How do you represent BlankNodes in RDF queries?

Capabilities of QLs

• Which RDF query languages can...
  • handle RDF schema-related queries?
  • do substring matches?
    • All that can do regex matching
• do regex matching?
  • RDQL, SPARQL, ...
• do recursive queries?
  • do template-matching queries?
  • do XSLT-like queries?
    • SPARQL's CONSTRUCT feature does a bit of that

How can queries be performed?

• Is there a programmatic query API? (what is a programmatic query?)
• How do I query generic RDBMS, SQL data using RDF query?
  • By dumping it to RDF (using e.g. D2R-Map) or by using a dynamic query translator like D2RQ (for Jena) or Federate.
• How can I query and return provenance information in RDF query? (what is provenance information?)
  • Use a query language capable of querying sets of named graphs, e.g. SPARQL or TriQL
• How do I represent RDF graphs in a (RDBMS, SQL) database and query them?
  • There's much existing work on this to be found out there.
• Why not use an RDF graph with blanks for querying RDF? (See: GraphMatchingQuery)

Testing the Proposed Specification

We're starting to see demo services based on the SPARQL spec from the RDF Data Access WG: DawgShows.

• RDFQueryTestCases
• RDFQueryTestcasesRequirements
• RdfQueryTestingBOF
• RdfQueryTestingBudapestBOF
• RdfQueryTestingBudapestMeeting
• Are there any test suites or test cases for RDF query ?
  • As it is a proposal, these cannot be written yet. However, one can attempt to implement suggestions made about the specification and report back with your findings.
• What summaries of RDF query are available?
• Are there any product-independent query languages?
  • Are there any product-independent languages of any kind? Most likely it will be extended, even if a core is agreed. In light of that, one could say SQL. I suspect this is not the intended question.

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