[Rdfapi-php-interest] SPARQL: SparqlEngine->matchPattern

[Stefan E. <ste...@ge...>]

Hello,

I have a question about the SparqlEngine in the case when DbModel is used
for RDF storage.

What do you think about replacing the following code in
SparqlEngine->matchPattern

$resultSet = $this->findTuplesMatchingOnePattern($qt[0], $newGraphList);
for ($i=1; $i<count($qt); $i++) {
	$rs = $this->findTuplesMatchingOnePattern($qt[$i], $newGraphList);
	$resultSet = $this->joinTuples($resultSet, $rs);
	if(!$resultSet)
		break;
}
if($finalRes != null){
	$finalRes = $this->joinTuples($finalRes,$resultSet);
}else{
	$finalRes = $resultSet;
}

by some code which generates a single SQL-Statement which would translate
SPAQL-Queries like 

PREFIX vcard <http://www.w3.org/2001/vcard-rdf/3.0#>
SELECT ?fullName ?age ?telval ?tel
WHERE { ?x vcard:age ?age .  ?x vcard:FN ?fullName. ?x vcard:TEL ?tel. ?tel
rdf:value ?telval}

into SQL-Queries like

select t0.object as age, t0.object_is as age_type, t1.object as fullName,
t1.object_is as fullName_type, t2.object as tel, t2.object_is as tel_type,
t3.object as telval, t3.object_is as telval_type from statements as t0
join statements as t1 on t0.subject=t1.subject join statements as t2 on
t0.subject=t2.subject join statements as t3 on t2.object=t3.subject where
1=1  and t0.predicate = 'http://www.w3.org/2001/vcard-rdf/3.0#age' and
t1.predicate = 'http://www.w3.org/2001/vcard-rdf/3.0#FN' and t2.predicate =
'http://www.w3.org/2001/vcard-rdf/3.0#TEL' and t3.predicate =
'http://www.w3.org/1999/02/22-rdf-syntax-ns#value'

?

I have done some basic work into this direction but I want to know what you
think about such a modification?

With kind regards
Stefan Erras