Availability:
:- use_module(library(semweb/rdf11)).
[semidet]{}(+Where)->), the
semantics of the goal remains the same. Preferably, constraints are
placed before the graph pattern as they often help the RDF
database to exploit its literal indexes. In the example below, the
database can choose between using the subject and/or predicate hash or
the ordered literal table.
{ Date >= "2000-01-01"^^xsd:date },
rdf(S, P, Date)
The following constraints are currently defined:
>,>====<<- The comparison operators are defined between numbers (of any recognised type), typed literals of the same type and langStrings of the same language.
- prefix(String, Pattern)
- substring(String, Pattern)
- word(String, Pattern)
- like(String, Pattern)
- icase(String, Pattern)
- Text matching operators that act on both typed literals and langStrings.
- lang_matches(Term, Pattern)
- Demands a full RDF term (Text@Lang) or a plain Lang term to match the language pattern Pattern.
The predicates rdf_where/1
and {}/1 are identical. The
rdf_where/1 variant is provided
to avoid ambiguity in applications where {}/1 is used for other
purposes. Note that it is also possible to write rdf11:{...}.