sweetrdf / simple-rdf
As simple as possible rdfInterface implementation
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Requires
- php: >=8.0
- sweetrdf/rdf-helpers: ^2
- sweetrdf/rdf-interface: ^2
- zozlak/rdf-constants: ^1.1
Requires (Dev)
Suggests
README
An RDF library for PHP implementing the https://github.com/sweetrdf/rdfInterface interface.
The aim was to provide as simple, short and clear implementation as possible. Performance wasn't really important (see the Performance chapter below).
It can be used as a baseline for testing performance of other libraries as well for testing interoperability of the rdfInterface implementations (e.g. making sure they work correctly with rdfInterface\Term
objects created by other library).
Installation
- Obtain the Composer
- Run
composer require sweetrdf/simple-rdf
- Run
composer require sweetrdf/quick-rdf-io
to install parsers and serializers.
Automatically generated documentation
https://sweetrdf.github.io/simpleRdf/namespaces/simplerdf.html
It's very incomplete but better than nothing.
RdfInterface documentation is included which explains the most important design decisions.
Usage
(you can also take a look at generic rdfInterface examples)
include 'vendor/autoload.php'; use simpleRdf\DataFactory as DF; $graph = new simpleRdf\Dataset(); $parser = new quickRdfIo\TriGParser(new simpleRdf\DataFactory()); $stream = fopen('pathToTurtleFile', 'r'); $graph->add($parser->parseStream($stream)); fclose($stream); // count edges in the graph echo count($graph); // go trough all edges in the graph foreach ($graph as $i) { echo "$i\n"; } // find all graph edges with a given subject echo $graph->copy(DF::quadTemplate(DF::namedNode('http://mySubject'))); // find all graph edges with a given predicate echo $graph->copy(DF::quadTemplate(null, DF::namedNode('http://myPredicate'))); // find all graph edges with a given object echo $graph->copy(DF::quadTemplate(null, null, DF::literal('value', 'en'))); // replace an edge in the graph $edge = DF::quad(DF::namedNode('http://edgeSubject'), DF::namedNode('http://edgePredicate'), DF::namedNode('http://edgeObject')); $graph[$edge] = $edge->withObject(DF::namedNode('http://anotherObject')); // find intersection with other graph $graph->copy($otherGraph); // immutable $graph->delete($otherGraph); // in-place // compute union with other graph $graph->union($otherGraph); // immutable $graph->add($otherGraph); // in-place // compute set difference with other graph $graph->copyExcept($otherGraph); // immutable $graph->delete($otherGraph); // in-place $serializer = new quickRdfIo\TurtleSerializer(); $stream = fopen('pathToOutputTurtleFile', 'w'); $serializer->serializeStream($stream, $graph); fclose($stream);
Performance
The simpleRdf\Dataset
class shouldn't be used to deal with larger amounts of quads.
Adding a quad has computational complexity of O(N)
where N
is the number of quads in the dataset.
It means adding n
quads has computational complexity of O(n!)
(read - it quickly gets out of hand with larger n
).
Just a sample results:
You get the idea, don't you?
Other operations are also not performant, e.g. all searches and in-place deletions have complexity of O(N)
and all methods returning a new copy of the dataset have complexity of O(N) + O(n!)
(where N
is number of quads in the dataset and n
the number of quads in the returned dataset).
If you are looking for a performant implementation, please take a look at the quickRdf.