Learning SPARQL, 2nd Edition

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 ([]). Tools that serialize triples do not have to save the prefixed name, as long as any new ones maintain all the same connections.

See Also graphprefixed nameserialization

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.

dataset

The collection of graphs that a given SPARQL query is querying. This collection consists of a default graph and optional named graphs.

See Also default graphnamed graph

default graph

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

Dublin Core

A popular standard vocabulary providing a basic set of metadata terms such as title, creator, and date