ODS.VirtSpongerLinkedDataHooksIntoSPARQLEx37

What?

Virtuoso SPARQL pragma for negating query optimizer.

Why?

There are situations where engine based query optimization isn't suitable for the SPARQL query at hand. In situations like this, you can apply a query pragma that signals to Virtuoso the need to negate its in-built query optimizer.

How?

Example with pragma sql:select-option

The following example demonstrates usage of the sql:select-option pragma.

DEFINE sql:select-option "order" 
PREFIX  ub:  <http://www.lehigh.edu/~zhp2/2004/0401/univ-bench.owl#>
SELECT *
WHERE
  {
    ?s ?p <http://www.Department0.University0.edu/GraduateCourse0>
  }
LIMIT 10 

• View the SPARQL Query Definition via SPARQL Protocol URL
• View the SPARQL Query Results via SPARQL Protocol URL

Sponger Usage Examples

• SPARQL Processor Usage Example
• RDF Proxy Service Example
• Browsing & Exploring RDF View Example Using ODE
• Browsing & Exploring RDF View Example Using iSPARQL
• Basic Sponger Cartridge Example
• HTTP Example for Extracting Metadata using CURL
• RESTFul Interaction Examples
• Flickr Cartridge Example
• MusicBrainz Metadatabase Example
• SPARQL Tutorial -- Magic of SPARUL and Sponger?

Related

• Sponger's Linked Data Middleware Hooks into SPARQL?
• Virtuoso Sponger
• Technical White Paper
• Supported Virtuoso Sponger Cartridges?
• SPARQL Sponger?
• Interacting with Sponger Middleware via RESTful Patterns?
• Interacting with Sponger Meta Cartridge via RESTful Patterns?
• Sponger Cartridge RDF Extractor?
• Extending SPARQL IRI Dereferencing with RDF Mappers?
• Programmer Guide for Virtuoso Linked Data Middleware ("Sponger")?
• Create RDF Custom Cartridge Tutorial?
• OpenLink-supplied Virtuoso Sponger Cartridges?
• Virtuoso Authentication Server?
• Virtuoso SPARQL OAuth Tutorial
• Virtuoso Sponger Access Control List (ACL) Setup?
• WebID Protocol & SPARQL Endpoint ACLs Tutorial?
• Virtuoso Documentation