RDF API tutorials

The following examples illustrate RDF API usage.

Language-tagged literals

To create language-tagged plain literals, you can use the rdf_literal() API function as follows:

rdf_literal('Hello!', 'en');
rdf_literal('Wazup?', 'en-US');
rdf_literal('¡Hola!', 'es');

Datatyped literals

When dealing with datatyped literals, RDF API functions allow you to work with standard PHP types for those cases where an obvious mapping exists between the PHP type and an equivalent XML Schema type; these are as follows:

boolean: XSD serialization: xsd:boolean; XSD unserialization: xsd:boolean
integer: XSD serialization: xsd:integer; XSD unserialization: xsd:integer, xsd:long, xsd:unsignedLong, xsd:unsignedInt
double: XSD serialization: xsd:double; XSD unserialization: xsd:double, xsd:float, xs:decimal
string: XSD serialization: xsd:string; XSD unserialization: xsd:string, xsd:normalizedString, xsd:token, xsd:language

For dealing with any other datatyped literals, wrap the lexical representation using rdf_literal(); some examples follow.

Base-64 encoded data

rdf_literal(base64_encode($text), NULL, xsd::base64Binary);

Dates and times

rdf_literal('2007-12-31T23:59:59Z', NULL, xsd::dateTime);
rdf_literal('2007-12-31', NULL, xsd::date);
rdf_literal('23:59:59.123-06:00', NULL, xsd::time);