Learning SPARQL

Glossary

binding

A pairing between a SPARQL variable and an RDF term. In practical terms, it’s a variable that has had a value assigned.

bnode

See blank node.

blank node

A subject or object in an RDF graph that has no identity. These are typically used to group together other values. For example, an address book entry may have an email address of “[e-mail]”, a phone number of 943-234-9664, and an address whose value is a blank node that has its own values: one for a street address, one for a city name, one for a postal code, and so forth. The resource that has these property values is represented by a prefixed name with an underscore prefix (for example, _:xyz) or as a pair of square braces ([]).

See Also graph, prefixed name.

cast

To convert a piece of data from one datatype to another—for example, converting the string “123” to the integer 123 or “2011-10-14T13:19:00”^^xsd:dateTime to “2011-10-14T13:19:00”^^xsd:string. “Cast” is a common programming term and not specific to SPARQL.

default graph

The triples in an RDF dataset that don’t belong to a named graph.

Dublin Core

A popular vocabulary providing a basic set of metadata terms such as title, creator, and date. Many specialized metadata vocabularies are usually based on Dublin Core.

See Also vocabulary.

endpoint

See SPARQL endpoint.

entailment

If A entails B, and A is true, then we know that B is true. If A is a complicated set of facts, it can be very handy to have technology such as an RDFS- or OWL-aware SPARQL processor to help ...