rdfapi-php-interest — general forum for RAP feature requests, bug reports, patches, and use cases

Re: [Rdfapi-php-interest] SPARQL engine - failed to handle OPTIONAL properly

[Sergey C. <rdf...@an...>]

Yep, unfortunately, I hit the same issue - check the bug database for the
project - it has a patch which helped me.
It seems like this project got abandoned by the maintainer - I'm even
thinking to switching to ARC ;(

               Sergey


On Thu, Nov 13, 2008 at 7:59 PM, Josef Petrák <jsp...@gm...> wrote:

> Hello all,
>
> we have tried to run a query to load foaf:names of a foaf:Group class,
> in which each foaf:name has different lang. The name in English lang
> is always present, the name in Czech lang is optional. The data are
> here http://keg.vse.cz/demo-groups.rdf Our SPARQL select was the
> following one:
>
> PREFIX foaf: <http://xmlns.com/foaf/0.1/>
> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
> SELECT ?group ?nameEn ?nameCs
> WHERE {
>        ?group rdf:type foaf:Group .
>        ?group foaf:name ?nameEn .
>        OPTIONAL { ?group foaf:name ?nameCs . FILTER (lang(?nameCs) = "cs")
> }
>        FILTER (lang(?nameEn) = "en")
> }
>
> But using RAP engine, we got only resources, which have both names bound:
>
> Array
> (
>    [0] => Array
>        (
>            [?group] => Resource Object
>                (
>                    [uri] => http://keg.vse.cz/resource/group/KIZI
>                )
>            [?nameEn] => Literal Object
>                (
>                    [label] => Department of Information and Knowledge
> Engineering
>                    [lang] => en
>                    [dtype] =>
>                )
>            [?nameCs] => Literal Object
>                (
>                    [label] => Katedra informačního a znalostního
> inženýrství
>                    [lang] => cs
>                    [dtype] =>
>                )
>        )
> )
>
> If we used e.g. Virtuoso SPARQL query engine service, we have got both
> resources:
>
>
> http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fkeg.vse.cz%2Fdemo-groups.rdf&should-sponge=soft&query=PREFIX+foaf%3A+%3Chttp%3A%2F%2Fxmlns.com%2Ffoaf%2F0.1%2F%3E%0D%0APREFIX+rdf%3A+%3Chttp%3A%2F%2Fwww.w3.org%2F1999%2F02%2F22-rdf-syntax-ns%23%3E%0D%0ASELECT+%3Fgroup+%3FnameEn+%3FnameCs%0D%0AWHERE+%7B%0D%0A%09%3Fgroup+rdf%3Atype+foaf%3AGroup+.%09%0D%0A%09%3Fgroup+foaf%3Aname+%3FnameEn+.%0D%0A%09OPTIONAL+%7B+%3Fgroup+foaf%3Aname+%3FnameCs+.+FILTER+%28lang%28%3FnameCs%29+%3D+%22cs%22%29+%7D%0D%0A%09FILTER+%28lang%28%3FnameEn%29+%3D+%22en%22%29%0D%0A%7D&format=text%2Fhtml&debug=on
>
> It might be a bug in RAP's SPARQL engine.
>
> Best regards
>
> Josef Petrak
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's
> challenge
> Build the coolest Linux based applications with Moblin SDK & win great
> prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Rdfapi-php-interest mailing list
> Rdf...@li...
> https://lists.sourceforge.net/lists/listinfo/rdfapi-php-interest
>



-- 
Sergey Chernyshev
http://www.sergeychernyshev.com/

[Rdfapi-php-interest] SPARQL engine - failed to handle OPTIONAL properly

[J. P. <jsp...@gm...>]

Hello all,

we have tried to run a query to load foaf:names of a foaf:Group class,
in which each foaf:name has different lang. The name in English lang
is always present, the name in Czech lang is optional. The data are
here http://keg.vse.cz/demo-groups.rdf Our SPARQL select was the
following one:

PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT ?group ?nameEn ?nameCs
WHERE {
	?group rdf:type foaf:Group .	
	?group foaf:name ?nameEn .
	OPTIONAL { ?group foaf:name ?nameCs . FILTER (lang(?nameCs) = "cs") }
	FILTER (lang(?nameEn) = "en")
}

But using RAP engine, we got only resources, which have both names bound:

Array
(
    [0] => Array
        (
            [?group] => Resource Object
                (
                    [uri] => http://keg.vse.cz/resource/group/KIZI
                )
            [?nameEn] => Literal Object
                (
                    [label] => Department of Information and Knowledge
Engineering
                    [lang] => en
                    [dtype] =>
                )
            [?nameCs] => Literal Object
                (
                    [label] => Katedra informačního a znalostního inženýrství
                    [lang] => cs
                    [dtype] =>
                )
        )
)

If we used e.g. Virtuoso SPARQL query engine service, we have got both
resources:

http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fkeg.vse.cz%2Fdemo-groups.rdf&should-sponge=soft&query=PREFIX+foaf%3A+%3Chttp%3A%2F%2Fxmlns.com%2Ffoaf%2F0.1%2F%3E%0D%0APREFIX+rdf%3A+%3Chttp%3A%2F%2Fwww.w3.org%2F1999%2F02%2F22-rdf-syntax-ns%23%3E%0D%0ASELECT+%3Fgroup+%3FnameEn+%3FnameCs%0D%0AWHERE+%7B%0D%0A%09%3Fgroup+rdf%3Atype+foaf%3AGroup+.%09%0D%0A%09%3Fgroup+foaf%3Aname+%3FnameEn+.%0D%0A%09OPTIONAL+%7B+%3Fgroup+foaf%3Aname+%3FnameCs+.+FILTER+%28lang%28%3FnameCs%29+%3D+%22cs%22%29+%7D%0D%0A%09FILTER+%28lang%28%3FnameEn%29+%3D+%22en%22%29%0D%0A%7D&format=text%2Fhtml&debug=on

It might be a bug in RAP's SPARQL engine.

Best regards

Josef Petrak

[Rdfapi-php-interest] Error in rdfapi-php SPARQL query using DBModel and union

[Soft W. <so...@gm...>]

Hello everyone.
I'm new to this list, but looks like this is the place to ask questions.

I'm trying to use rdfapi-php to load and query large ontology.

What I found is that executing the query 


SELECT distinct ?name 
WHERE {
      {
       ?unique_id rdfs:label ?name.
       FILTER regex(str(?name), '<value>').
      } union {
       ?unique_id rdfs:label ?name2.
       FILTER regex(str(?name2), '<value>').
       ?unique_id oboInOwl:hasExactSynonym  ?another_id  .
        ?another_id rdfs:label ?name  .        
      }
}

Where <value> is some keyword I'm trying to look up in the ontology by
matching the regexp against the 
name with all cross-referenced keywords.

Causes a db exception and wrong query.

In fact the point of the query was to attach 2 sets of data via union
1. set of data that directly matches the pattern
2. set of data that has synonyms of the matched pattern

and return 2 column ?name from the union.

The SQLGenerator class generates the 


QUERY: (SELECT DISTINCT t0.object as "t0.value_v_name", t0.object_is as
"t0.is_v_name", t0.l_language as "t0.lang_v_name", t0.l_datatype as
"t0.type_v_name" FROM statements as t0 WHERE 1 AND t0.predicate =
'http://www.w3.org/2000/01/rdf-schema#label' AND (CASE t0.object_is WHEN "b"
THEN "" ELSE t0.object END) REGEXP "<value>") UNION (SELECT DISTINCT
t0.object as "t0.value_v_name", t0.object_is as "t0.is_v_name",
t0.l_language as "t0.lang_v_name", t0.l_datatype as "t0.type_v_name" FROM
statements as t0 LEFT JOIN statements as t1 ON t0.modelID = t1.modelID LEFT
JOIN statements as t0 ON t0.modelID = t0.modelID AND t0.object = t0.object
WHERE 1 AND t0.predicate = 'http://www.w3.org/2000/01/rdf-schema#label'  AND
t1.predicate =
'http://www.geneontology.org/formats/oboInOwl#hasExactSynonym' AND
t1.subject = t0.subject AND t1.subject_is = t0.subject_is  AND t0.predicate
= 'http://www.w3.org/2000/01/rdf-schema#label' AND t0.subject = t1.object
AND t0.subject_is = t1.object_is AND (CASE t0.object_is WHEN "b" THEN ""
ELSE t0.object END) REGEXP "<value>")


Exception: ADOdb error: Not unique table/alias: 't0'


In general, you can see that the second query in the union is incorrect.

I think the error is in these commented lines:
Class SqlGenerator
    function getTripleSql(QueryTriple $triple, GraphPattern $graphPattern,
$arResultVars)

.......................
.......................
.......................
        /**
        *   SELECT part
        *   We do select only the columns we need for variables
        */
        if (SparqlVariable::isVariable($subject)) {
            if
(isset($this->arUnionVarAssignments[$this->nUnionCount][$subject])) {
                //already selected -> add equality check
                $bWhereEqualitySubject = true;
                $this->arUsedVarTypes[$subject]['s'] = true;
            } else {
      ->          //if (isset($this->arVarAssignments[$subject][0])) {
      ->           //   $strTablePrefix =
$this->arVarAssignments[$subject][0];
      ->         // }
                $this->arVarAssignments[$subject] = array($strTablePrefix,
's');
                $this->arUnionVarAssignments[$this->nUnionCount][$subject] =
array($strTablePrefix, 's');
                $this->arUsedVarTypes[$subject]['s'] = true;
                if (self::isResultVar($subject, $arResultVars)) {
                    //new variable that needs to be selected
                    $arSelect[$subject] = $this->createVariableSelectArray(
                        's', $subject, $strTablePrefix
                    );
                    if (isset($this->arUsedVarAssignments[$subject])) {
                        $arRefVars[$subject] = $strTablePrefix . '.subject';
                    } else {
                        $this->arUsedVarAssignments[$subject] =
$strTablePrefix . '.subject';
                    }
                }
            }
        }

        if (SparqlVariable::isVariable($predicate)) {
            if
(isset($this->arUnionVarAssignments[$this->nUnionCount][$predicate])) {
                //already selected -> add equality check
                $bWhereEqualityPredicate = true;
                $this->arUsedVarTypes[$predicate]['p'] = true;
            } else {
        ->       // if (isset($this->arVarAssignments[$predicate][0])) {
        ->      //     $strTablePrefix =
$this->arVarAssignments[$predicate][0];
        ->       // }
                $this->arVarAssignments[$predicate] = array($strTablePrefix,
'p');
                $this->arUnionVarAssignments[$this->nUnionCount][$predicate]
= array($strTablePrefix, 'p');
                $this->arUsedVarTypes[$predicate]['p'] = true;
                if (self::isResultVar($predicate, $arResultVars)) {
                    $arSelect[$predicate] =
$this->createVariableSelectArray(
                        'p', $predicate, $strTablePrefix
                    );
                    if (isset($this->arUsedVarAssignments[$predicate])) {
                        $arRefVars[$predicate] = $strTablePrefix .
'.predicate';
                    } else {
                        $this->arUsedVarAssignments[$predicate] =
$strTablePrefix . '.predicate';
                    }
                }
            }
        }

        if (SparqlVariable::isVariable($object)) {
            if
(isset($this->arUnionVarAssignments[$this->nUnionCount][$object])) {
                //already selected -> add equality check
                $bWhereEqualityObject = true;
                $this->arUsedVarTypes[$object]['o'] = true;
            } else {
        ->       //if (isset($this->arVarAssignments[$object][0])) {
        ->        //    $strTablePrefix =
$this->arVarAssignments[$object][0];
        ->        // }
                $this->arVarAssignments[$object] = array($strTablePrefix,
'o');
                $this->arUnionVarAssignments[$this->nUnionCount][$object] =
array($strTablePrefix, 'o');
                $this->arUsedVarTypes[$object]['o'] = true;
                if (self::isResultVar($object, $arResultVars)) {
                    $arSelect[$object] = $this->createVariableSelectArray(
                        'o', $object, $strTablePrefix
                    );
                    if (isset($this->arUsedVarAssignments[$object])) {
                        $arRefVars[$object] = $strTablePrefix . '.object';
                    } else {
                        $this->arUsedVarAssignments[$object] =
$strTablePrefix . '.object';
                    }
                }
                if (isset($this->query->varLanguages[$object])
                 && $this->query->varLanguages[$object] !== null
                ) {
                    $strWhereEquality .=
                        ' AND ' . $strTablePrefix . '.l_language = "'
                        . addslashes($this->query->varLanguages[$object]) .
'"';
                }
                if (isset($this->query->varDatatypes[$object])
                 && $this->query->varDatatypes[$object] !== null
                ) {
                    $strWhereEquality .=
                        ' AND ' . $strTablePrefix . '.l_datatype = "'
                        . addslashes($this->query->varDatatypes[$object]) .
'"';
                }
            }
        }




When commented, the query is produced correctly
 (SELECT DISTINCT t0.object as ".value_v_name", t0.object_is as
".is_v_name", t0.l_language as ".lang_v_name", t0.l_datatype as
".type_v_name" FROM statements as t0 WHERE 1 AND t0.predicate =
'http://www.w3.org/2000/01/rdf-schema#label' AND (CASE t0.object_is WHEN "b"
THEN "" ELSE t0.object END) REGEXP "<value>") UNION (SELECT DISTINCT
t2.object as ".value_v_name", t2.object_is as ".is_v_name", t2.l_language as
".lang_v_name", t2.l_datatype as ".type_v_name" FROM statements as t0 LEFT
JOIN statements as t1 ON t0.modelID = t1.modelID LEFT JOIN statements as t2
ON t0.modelID = t2.modelID AND t0.object = t2.object WHERE 1 AND
t0.predicate = 'http://www.w3.org/2000/01/rdf-schema#label'  AND
t1.predicate =
'http://www.geneontology.org/formats/oboInOwl#hasExactSynonym' AND
t1.subject = t0.subject AND t1.subject_is = t0.subject_is  AND t2.predicate
= 'http://www.w3.org/2000/01/rdf-schema#label' AND t2.subject = t1.object
AND t2.subject_is = t1.object_is AND (CASE t0.object_is WHEN "b" THEN ""
ELSE t0.object END) REGEXP "<value>")


I also added extra parameter to the createVariableSelectArray method to
control the column prefix which is in my case is always empty, since I 'm
not sure why do we need a table name prefix here especially if we run union.

    protected function createVariableSelectArray($chType, $varname,
$strTablePrefix, $strColumnNamePrefix = "")
    {
        $var = $this->query->getResultVar($varname);
        if ($var !== false) {
            if ((string)$var != $varname) {
                //copy over var assignments
                $this->arVarAssignments[(string)$var] =
$this->arVarAssignments[$varname];
            }

            //works on non-* only
            $func = $var->getFunc();
            if ($func != null) {
                if ($func == 'datatype') {
                    if ($chType != 'o') {
                        throw new SparqlEngineDb_SqlGeneratorException(
                            'datatype() works on objects only'
                        );
                    }
                    return array(
                        $strTablePrefix . '.l_datatype as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameValue($var) . '"',
                        '"r"' .                      ' as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameIs($var) . '"',
                        '""' .                       ' as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameLanguage($var) . '"',
                        '""' .                       ' as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameDatatype($var) . '"',
                    );
                } else if ($func == 'lang') {
                    if ($chType != 'o') {
                        throw new SparqlEngineDb_SqlGeneratorException(
                            'lang() works on objects only'
                        );
                    }
                    return array(
                        $strTablePrefix . '.l_language as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameValue($var) . '"',
                        '"l"' .                      ' as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameIs($var) . '"',
                        '""' .                       ' as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameLanguage($var) . '"',
                        '""' .                       ' as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameDatatype($var) . '"',
                    );
                } else {
                    throw new SparqlEngineDb_SqlGeneratorException(
                        'Unsupported function for select "' . $func . '"'
                    );
                }
            }
        }

        switch ($chType) {
            case 's':
                return array(
                    $strTablePrefix . '.subject as "'    .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameValue($varname) . '"',
                    $strTablePrefix . '.subject_is as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameIs($varname) . '"'
                );
            case 'p':
                return array(
                    $strTablePrefix . '.predicate as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameValue($varname) . '"'
                );
            case 'o':
                return array(
                    $strTablePrefix . '.object as "'     .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameValue($varname) . '"',
                    $strTablePrefix . '.object_is as "'  .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameIs($varname) . '"',
                    $strTablePrefix . '.l_language as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameLanguage($varname) .
'"',
                    $strTablePrefix . '.l_datatype as "' .
$strColumnNamePrefix . '.' . $this->getSqlVariableNameDatatype($varname) .
'"',
                );
            default:
                throw new SparqlEngineDb_SqlGeneratorException(
                    'Unknown sentence type "' . $chType . "', one of (s,p,o)
expected"
                );
        }
    }//protected function createVariableSelectArray($chType, $value,
$strTablePrefix)



This change needs to be coupled with this snippet of code that skips the
check for the table prefix
In all of these methods for XML, HTML, Text and Default renderers.

        createSubjectFromDbRecordSetPart
        createPredicateFromDbRecordSetPart
        createObjectFromDbRecordSetPart


        foreach ( array_keys($dbRecordSet->fields) as $field){
        	if ( substr($field,0,1) != '.') {
        		$noprefix = false;
        		break;
        	}
        }
        if ( $noprefix ){
        	$strVarBase = '';
        }

[Rdfapi-php-interest] RDF-Schema reasoning

[Adam Z. <poc...@wp...>]

Its my first mail here so hello everybody :-)

I would like to create php  aplication wich carry out  reasoning proces 
using RDF-Schema and rdfapi.
When i was reading documentation on rdfapi home page i noticed that this 
part in menu is nonactive:
- inference engine supporting RDF-Schema reasoning and some OWL entailments.
Is rdfapi including functions wich can help me  make reasoning using RDFS ?

[Rdfapi-php-interest] Need help with german Umlaut

[Susanne B. <ma...@su...>]

Hello.

I am from Germany and I need to use german Umlauts in my rdf-file. I tried to use 
<?xml version="1.0" encoding="utf-8"?>

as header but I always get this error:

Fatal error: RDFAPI error (class: parser; method: generateModel): XML-parser-error 9 in Line 71 of input document. in C:\Program Files\xampplite\htdocs\IRLscreen\rdfapi-php\api\syntax\RdfParser.php on line 2225


Line 71 is the line there the first u Umlaut is located. If I choose ISO-8859-1 as encoding I get no parse error but the u Umlaut is A with tilde followed by "a quarter".

Can anyone help me please?

Greets

Susanne

Re: [Rdfapi-php-interest] SPARQL OPTIONAL error

[Will D. <ma...@wi...>]

Thanks Sergey! I might have submitted a patch in the first instance, 
only my head was spinning a little by the time I'd managed to figure out 
all the code and I wanted somebody who knew it already to confirm sanity 
first. But since there are two others now to support the fix...hopefully 
submitting a patch will make the necessary difference (I think maybe the 
person who was maintaining the SPARQL client disappeared because the 
only svn commits I've noticed look to be for things to fix pubby).

Regards,
Will


Sergey Chernyshev wrote:
> Yep, looks like it works - I've added a patch to sf.net 
> <http://sf.net> site.
>
>        Sergey
>
>
> On Fri, Aug 15, 2008 at 12:34 PM, Sergey Chernyshev 
> <rdf...@an... 
> <mailto:rdf...@an...>> wrote:
>
>     Thanks, Will, I'll give it a shot!
>
>               Sergey
>
>
>
>     On Thu, Aug 14, 2008 at 6:06 AM, Will Daniels
>     <ma...@wi... <mailto:ma...@wi...>> wrote:
>
>         This sounds like a bug I filed back in March (fix provided)
>         though I don't remember the details precisely now to confirm
>         100% that it's the same issue:
>
>         http://sourceforge.net/tracker/index.php?func=detail&aid=1928579&group_id=63257&atid=503361
>         <http://sourceforge.net/tracker/index.php?func=detail&aid=1928579&group_id=63257&atid=503361>
>
>         Unfortunately, the bugs do not appear to be attended to. If
>         anybody can and wants to grant me access to the svn, I'd be
>         happy to fix a few.
>
>         Regards,
>         Will
>
>         Sergey Chernyshev wrote:
>>         It looks like RAP is having a significant issue with handling
>>         OPTIONAL blocks - when variable from mandatory part is also
>>         used within OPTIONAL block and non-optional part of the query
>>         matches nothing, OPTIONAL block still gets executed as if
>>         there was no mandatory part of the query.
>>
>>         For example, query like this:
>>         *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
>>         *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
>>         *SELECT ?blog, ?title WHERE {*
>>         *<http://www.sergeychernyshev.com/sergey> foaf:weblog ?blog .*
>>         *OPTIONAL { ?blog dc:title ?title}*
>>         *}*
>>
>>         ran against http://www.sergeychernyshev.com/sergey.rdf (where
>>         foaf:weblog triple exists) works fine and returns one entry
>>         with defined ?blog and empty ?title.
>>
>>         But query
>>         *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
>>         *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
>>         *SELECT ?blog, ?title WHERE {*
>>         *<http://www.w3.org/People/Berners-Lee/card#i> foaf:weblog
>>         ?blog .*
>>         *OPTIONAL { ?blog dc:title ?title}*
>>         *}*
>>         ran against
>>         http://www.sergeychernyshev.com/profile/tests/timbl.rdf
>>         (where no foaf:weblog triples exist) returns ?blog variables
>>         bound to all subjects that have dc:title properties as if
>>         this query was ran
>>         *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
>>         *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
>>         *SELECT ?blog, ?title WHERE {*
>>         *OPTIONAL { ?blog dc:title ?title}*
>>         *}*
>>
>>         I don't even know how to approach this! Will appreciate any help.
>>
>>         Thank you,
>>
>>                   Sergey
>>
>>
>>         -- 
>>         Sergey Chernyshev
>>         http://www.sergeychernyshev.com/
>>         ------------------------------------------------------------------------
>>
>>         -------------------------------------------------------------------------
>>         This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
>>         Build the coolest Linux based applications with Moblin SDK & win great prizes
>>         Grand prize is a trip for two to an Open Source event anywhere in the world
>>         http://moblin-contest.org/redirect.php?banner_id=100&url=/ <http://moblin-contest.org/redirect.php?banner_id=100&url=/>
>>         ------------------------------------------------------------------------
>>
>>         _______________________________________________
>>         Rdfapi-php-interest mailing list
>>         Rdf...@li... <mailto:Rdf...@li...>
>>         https://lists.sourceforge.net/lists/listinfo/rdfapi-php-interest
>>           
>
>
>
>
>     -- 
>     Sergey Chernyshev
>     http://www.sergeychernyshev.com/
>
>
>
>
> -- 
> Sergey Chernyshev
> http://www.sergeychernyshev.com/

Re: [Rdfapi-php-interest] SPARQL OPTIONAL error

[Sergey C. <rdf...@an...>]

Yep, looks like it works - I've added a patch to sf.net site.

       Sergey


On Fri, Aug 15, 2008 at 12:34 PM, Sergey Chernyshev <
rdf...@an...> wrote:

> Thanks, Will, I'll give it a shot!
>
>           Sergey
>
>
>
> On Thu, Aug 14, 2008 at 6:06 AM, Will Daniels <ma...@wi...>wrote:
>
>>  This sounds like a bug I filed back in March (fix provided) though I
>> don't remember the details precisely now to confirm 100% that it's the same
>> issue:
>>
>>
>> http://sourceforge.net/tracker/index.php?func=detail&aid=1928579&group_id=63257&atid=503361
>>
>> Unfortunately, the bugs do not appear to be attended to. If anybody can
>> and wants to grant me access to the svn, I'd be happy to fix a few.
>>
>> Regards,
>> Will
>>
>> Sergey Chernyshev wrote:
>>
>> It looks like RAP is having a significant issue with handling OPTIONAL
>> blocks - when variable from mandatory part is also used within OPTIONAL
>> block and non-optional part of the query matches nothing, OPTIONAL block
>> still gets executed as if there was no mandatory part of the query.
>>
>> For example, query like this:
>> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
>> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
>> *SELECT ?blog, ?title WHERE {*
>>  *<http://www.sergeychernyshev.com/sergey> foaf:weblog ?blog .*
>> *OPTIONAL { ?blog dc:title ?title}*
>>  *}*
>>
>> ran against http://www.sergeychernyshev.com/sergey.rdf (where foaf:weblog
>> triple exists) works fine and returns one entry with defined ?blog and empty
>> ?title.
>>
>> But query
>> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
>> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
>> *SELECT ?blog, ?title WHERE {*
>>  *<http://www.w3.org/People/Berners-Lee/card#i> foaf:weblog ?blog .*
>> *OPTIONAL { ?blog dc:title ?title}*
>>  *}*
>>  ran against http://www.sergeychernyshev.com/profile/tests/timbl.rdf(where no foaf:weblog triples exist) returns ?blog variables bound to all
>> subjects that have dc:title properties as if this query was ran
>> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
>> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
>> *SELECT ?blog, ?title WHERE {*
>>  *OPTIONAL { ?blog dc:title ?title}*
>>  *}*
>>
>> I don't even know how to approach this! Will appreciate any help.
>>
>> Thank you,
>>
>>           Sergey
>>
>>
>>  --
>> Sergey Chernyshev
>> http://www.sergeychernyshev.com/
>>
>> ------------------------------
>>
>> -------------------------------------------------------------------------
>> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
>> Build the coolest Linux based applications with Moblin SDK & win great prizes
>> Grand prize is a trip for two to an Open Source event anywhere in the worldhttp://moblin-contest.org/redirect.php?banner_id=100&url=/
>>
>> ------------------------------
>>
>> _______________________________________________
>> Rdfapi-php-interest mailing lis...@li...https://lists.sourceforge.net/lists/listinfo/rdfapi-php-interest
>>
>>
>
>
> --
> Sergey Chernyshev
> http://www.sergeychernyshev.com/
>



-- 
Sergey Chernyshev
http://www.sergeychernyshev.com/

Re: [Rdfapi-php-interest] SPARQL OPTIONAL error

[Sergey C. <rdf...@an...>]

Thanks, Will, I'll give it a shot!

          Sergey


On Thu, Aug 14, 2008 at 6:06 AM, Will Daniels <ma...@wi...>wrote:

>  This sounds like a bug I filed back in March (fix provided) though I
> don't remember the details precisely now to confirm 100% that it's the same
> issue:
>
>
> http://sourceforge.net/tracker/index.php?func=detail&aid=1928579&group_id=63257&atid=503361
>
> Unfortunately, the bugs do not appear to be attended to. If anybody can and
> wants to grant me access to the svn, I'd be happy to fix a few.
>
> Regards,
> Will
>
> Sergey Chernyshev wrote:
>
> It looks like RAP is having a significant issue with handling OPTIONAL
> blocks - when variable from mandatory part is also used within OPTIONAL
> block and non-optional part of the query matches nothing, OPTIONAL block
> still gets executed as if there was no mandatory part of the query.
>
> For example, query like this:
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
>  *<http://www.sergeychernyshev.com/sergey> foaf:weblog ?blog .*
> *OPTIONAL { ?blog dc:title ?title}*
>  *}*
>
> ran against http://www.sergeychernyshev.com/sergey.rdf (where foaf:weblog
> triple exists) works fine and returns one entry with defined ?blog and empty
> ?title.
>
> But query
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
>  *<http://www.w3.org/People/Berners-Lee/card#i> foaf:weblog ?blog .*
> *OPTIONAL { ?blog dc:title ?title}*
>  *}*
>  ran against http://www.sergeychernyshev.com/profile/tests/timbl.rdf(where no foaf:weblog triples exist) returns ?blog variables bound to all
> subjects that have dc:title properties as if this query was ran
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
>  *OPTIONAL { ?blog dc:title ?title}*
>  *}*
>
> I don't even know how to approach this! Will appreciate any help.
>
> Thank you,
>
>           Sergey
>
>
>  --
> Sergey Chernyshev
> http://www.sergeychernyshev.com/
>
> ------------------------------
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the worldhttp://moblin-contest.org/redirect.php?banner_id=100&url=/
>
> ------------------------------
>
> _______________________________________________
> Rdfapi-php-interest mailing lis...@li...https://lists.sourceforge.net/lists/listinfo/rdfapi-php-interest
>
>


-- 
Sergey Chernyshev
http://www.sergeychernyshev.com/

Re: [Rdfapi-php-interest] SPARQL OPTIONAL error

[Will D. <ma...@wi...>]

This sounds like a bug I filed back in March (fix provided) though I 
don't remember the details precisely now to confirm 100% that it's the 
same issue:

http://sourceforge.net/tracker/index.php?func=detail&aid=1928579&group_id=63257&atid=503361 
<http://sourceforge.net/tracker/index.php?func=detail&aid=1928579&group_id=63257&atid=503361>

Unfortunately, the bugs do not appear to be attended to. If anybody can 
and wants to grant me access to the svn, I'd be happy to fix a few.

Regards,
Will

Sergey Chernyshev wrote:
> It looks like RAP is having a significant issue with handling OPTIONAL 
> blocks - when variable from mandatory part is also used within 
> OPTIONAL block and non-optional part of the query matches nothing, 
> OPTIONAL block still gets executed as if there was no mandatory part 
> of the query.
>
> For example, query like this:
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
> *<http://www.sergeychernyshev.com/sergey> foaf:weblog ?blog .*
> *OPTIONAL { ?blog dc:title ?title}*
> *}*
>
> ran against http://www.sergeychernyshev.com/sergey.rdf (where 
> foaf:weblog triple exists) works fine and returns one entry with 
> defined ?blog and empty ?title.
>
> But query
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
> *<http://www.w3.org/People/Berners-Lee/card#i> foaf:weblog ?blog .*
> *OPTIONAL { ?blog dc:title ?title}*
> *}*
> ran against http://www.sergeychernyshev.com/profile/tests/timbl.rdf 
> (where no foaf:weblog triples exist) returns ?blog variables bound to 
> all subjects that have dc:title properties as if this query was ran
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
> *OPTIONAL { ?blog dc:title ?title}*
> *}*
>
> I don't even know how to approach this! Will appreciate any help.
>
> Thank you,
>
>           Sergey
>
>
> -- 
> Sergey Chernyshev
> http://www.sergeychernyshev.com/
> ------------------------------------------------------------------------
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> ------------------------------------------------------------------------
>
> _______________________________________________
> Rdfapi-php-interest mailing list
> Rdf...@li...
> https://lists.sourceforge.net/lists/listinfo/rdfapi-php-interest
>   

[Rdfapi-php-interest] SPARQL OPTIONAL error

[Sergey C. <rdf...@an...>]

It looks like RAP is having a significant issue with handling OPTIONAL
blocks - when variable from mandatory part is also used within OPTIONAL
block and non-optional part of the query matches nothing, OPTIONAL block
still gets executed as if there was no mandatory part of the query.

For example, query like this:
*PREFIX dc: <http://purl.org/dc/elements/1.1/>*
*PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
*SELECT ?blog, ?title WHERE {*
*<http://www.sergeychernyshev.com/sergey> foaf:weblog ?blog .*
*OPTIONAL { ?blog dc:title ?title}*
*}*

ran against http://www.sergeychernyshev.com/sergey.rdf (where foaf:weblog
triple exists) works fine and returns one entry with defined ?blog and empty
?title.

But query
*PREFIX dc: <http://purl.org/dc/elements/1.1/>*
*PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
*SELECT ?blog, ?title WHERE {*
*<http://www.w3.org/People/Berners-Lee/card#i> foaf:weblog ?blog .*
*OPTIONAL { ?blog dc:title ?title}*
*}*
ran against http://www.sergeychernyshev.com/profile/tests/timbl.rdf (where
no foaf:weblog triples exist) returns ?blog variables bound to all subjects
that have dc:title properties as if this query was ran
*PREFIX dc: <http://purl.org/dc/elements/1.1/>*
*PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
*SELECT ?blog, ?title WHERE {*
*OPTIONAL { ?blog dc:title ?title}*
*}*

I don't even know how to approach this! Will appreciate any help.

Thank you,

          Sergey


-- 
Sergey Chernyshev
http://www.sergeychernyshev.com/

[Rdfapi-php-interest] Fwd: [BUG] BaseURI

[Sergey C. <rdf...@an...>]

For some reason I wasn't on the list. Resending it again.

---------- Forwarded message ----------
From: Sergey Chernyshev <rdf...@an...>
Date: Sat, Aug 9, 2008 at 1:54 AM
Subject: [BUG] BaseURI
To: rdf...@li...


I think there is a bug with the base URI handling in RAP - essentially it's
adding # sign at the end of the URI which makes it different from original
base URI used to load the document.

While it might be useful to do that when there are lots of concatenations
where you need to add hash sign to get local URI, it's not correct way to
doing this as it makes this URI different from what might be looked for
within the document - basically this URI can be referenced within the
document itself to identify the relationship between other objects and the
document (used primarily with foaf:PersonalProfileDocument predicate).

I hope this is an easy fix, but it's still hard for me to grasp all the RAP
to be able to write a patch myself.

Thank you,

           Sergey


-- 
Sergey Chernyshev
http://www.sergeychernyshev.com/

[Rdfapi-php-interest] Installing RAP in EASYPHP-1.7 Not able to install

[Nallanchakravarthy R. A. <nra...@ya...>]

Hello
      EASYPHP-1.7 is a combination of (PHP 4.3.3,APACHE,MYSQL) i am unable to 
install RAP in EASYPHP-1.7. Can anybody help me in this regard.

Awaiting for your reply

Thanking you

N.R.Ananthanarayanen





      

[Rdfapi-php-interest] Performance with statements stored as varchar and indexes on varchar

[Kunal J. <ku...@eo...>]

Hi All,

I am evalutating RAP and was looking into the table structure created by RAP to store the statements. 
The table is as follows

CREATE TABLE `statements` (
  `modelID` bigint(20) NOT NULL,
  `subject` varchar(255) NOT NULL,
  `predicate` varchar(255) NOT NULL,
  `object` text,
  `l_language` varchar(255) DEFAULT '',
  `l_datatype` varchar(255) DEFAULT '',
  `subject_is` varchar(1) NOT NULL,
  `object_is` varchar(1) NOT NULL,
  KEY `s_mod_idx` (`modelID`),
  KEY `s_sub_pred_idx` (`subject`(200),`predicate`(200)),
  KEY `s_sub_idx` (`subject`(200)),
  KEY `s_pred_idx` (`predicate`(200)),
  KEY `s_obj_idx` (`object`(250))
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

For my evaluation, i have around 5 million triples currently and the number is growing. And with this kind of structure the size of the db will be very large as indexes are created on varchar and the performance will also degrade.

Are there any performance numbers for RAP available, which will help me in my evaluation ?

Thanks
Kunal

[Rdfapi-php-interest] Storage Problem

[<Kar...@gm...>]

i have an ontology of size 200 KB. When i try to load this with rdf api tool using MemModel it gives sometimes an error memory exhausted or the ontology is wrongly loaded.
 For example:
 URI of my ontology is http://www.owl-ontologies.com/ontology/muenze.owl#
 and URI of the instance should be http://www.owl-ontologies.com/ontology/muenze.owl#Instance
 but there are instances with wrong URI i.e. http://www.owl-ontologies.com/ontology/instance

 Is there any limit for the size of ontology being loaded with rdf-api?

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[Rdfapi-php-interest] ModelFactory::getInfModelF() bug?

[Peter B. <pb...@xs...>]

Hi,

I'm using RAP V0.9.6 and write

$im = ModelFactory::getInfModelF();

which I suppose should work (or shouldn't it?), but it returns a message 
about InfModel not being found in InfModelF.php.

I changed ModelFactory.php and replaced
         require_once RDFAPI_INCLUDE_DIR . 'infModel/InfModelF.php';
by
         require_once RDFAPI_INCLUDE_DIR . 'infModel/InfModelP.php';

which removes the problem.

Bye,
Peter

[Rdfapi-php-interest] SPARQL endpoints

[B P <bp...@go...>]

Hi, a second question for today.
Who is responsible for the sparql endpoints at
www4.wiwiss.fu-berlin.de? Are they "stable"? We need some Sparql
endpoint to use as part of a proof-of-concept-demo and yours could fit
in nicely. Are they documented somewhere or could someone post a list
of classes and properties?
All I have found is this on http://esw.w3.org/topic/SparqlEndpoints:

World Factbook (Freie Universität Berlin)
   *  URL: http://www4.wiwiss.fu-berlin.de/factbook/sparql
   *  webform: http://www4.wiwiss.fu-berlin.de/factbook/snorql
   * status: alive
   * data exposed: Country statistics from the CIA World Factbook

Project Gutenberg Metadata (Freie Universität Berlin)
   * URL: http://www4.wiwiss.fu-berlin.de/gutendata/sparql
   * webform: http://www4.wiwiss.fu-berlin.de/gutendata/snorql
   * status: alive
   *  data exposed: Data on authors and literary works from Project Gutenberg

http://www4.wiwiss.fu-berlin.de/factbook/snorql seems to work but
http://www4.wiwiss.fu-berlin.de/gutendata/snorql gets redirected to
http://10.119.0.68/

Greetings
Bart

Re: [Rdfapi-php-interest] Sparql bugs?

[Olivier G. <o.g...@no...>]

> FILTER (?start > "2008-11-26T23:59:59Z)

Missing an end quote ?

Re: [Rdfapi-php-interest] Sparql bugs?

[Chris B. <ch...@bi...>]

Hi Bart,

please put the bug report in the tracker anyway.

But also send it to Christian Weiske (cw...@cw...) who 
developed the SPARQL engine and hopefully can fix this quickly.

Cheers

Chris


--
Prof. Dr. Chris Bizer
Freie Universität Berlin
Phone: +49 30 838 54057
Mail: ch...@bi...
Web: www.bizer.de

----- Original Message ----- 
From: "B P" <bp...@go...>
To: <Rdf...@li...>
Sent: Monday, June 09, 2008 12:37 PM
Subject: [Rdfapi-php-interest] Sparql bugs?


> Hi,
> where should one post bug reports/questions for Rdfapi-php. I have a 
> problem
> with some sparql queries but the bugs over at
> http://sourceforge.net/tracker/?group_id=63257 seem to be 
> unattended?
> The problem:
> In a FILTER ">" (biger that) is not accepted.
> Example:
> FILTER (?start > "2008-11-26T23:59:59Z) works fine but FILTER 
> (?start >
> "2008-11-26T23:59:59Z) causes the following error:
> Fatal error: Uncaught exception 
> 'SparqlEngineDb_SqlGeneratorException' with
> message 'Unsupported tree type: ' in
> /home/space/vernkirche/htdocs/sw/includes/rdfapi-php/api/sparql/SparqlEngineDb/FilterGenerator.php:124
> Stack trace: #0
> /home/space/vernkirche/htdocs/sw/includes/rdfapi-php/api/sparql/SparqlEngineD....
>
> Greetings
> Bart
>


--------------------------------------------------------------------------------


> -------------------------------------------------------------------------
> Check out the new SourceForge.net Marketplace.
> It's the best place to buy or sell services for
> just about anything Open Source.
> http://sourceforge.net/services/buy/index.php


--------------------------------------------------------------------------------


> _______________________________________________
> Rdfapi-php-interest mailing list
> Rdf...@li...
> https://lists.sourceforge.net/lists/listinfo/rdfapi-php-interest
> 

[Rdfapi-php-interest] Sparql bugs?

[B P <bp...@go...>]

Hi,
where should one post bug reports/questions for Rdfapi-php. I have a problem
with some sparql queries but the bugs over at
http://sourceforge.net/tracker/?group_id=63257 seem to be unattended?
The problem:
In a FILTER ">" (biger that) is not accepted.
Example:
FILTER (?start > "2008-11-26T23:59:59Z) works fine but FILTER (?start >
"2008-11-26T23:59:59Z) causes the following error:
Fatal error: Uncaught exception 'SparqlEngineDb_SqlGeneratorException' with
message 'Unsupported tree type: ' in
/home/space/vernkirche/htdocs/sw/includes/rdfapi-php/api/sparql/SparqlEngineDb/FilterGenerator.php:124
Stack trace: #0
/home/space/vernkirche/htdocs/sw/includes/rdfapi-php/api/sparql/SparqlEngineD....

Greetings
Bart

[Rdfapi-php-interest] RDQL - Query with sameAs

[Axel H. <a_...@we...>]

Hello,

 

i am new to rdfapid and have a little question. How can rdfapi use the
property "sameAs" ?

 

In my Test case, i've an class "superclass1" and "superclass2". 
superclass1 is defined as "sameAs superclass2" and superclass2 is defined as
"sameAs superclass1"

 

A third class is "subclass1" and is defined as "subClass of superclass1" 

 

The following query gives me subclass1 as result:

 

SELECT  *  WHERE (?x, rdfs:subClassOf, <http://myUrl/test#superclass1>)';

 

Why do i not get the same result with

SELECT  *  WHERE (?x, rdfs:subClassOf, <http://myUrl/test#superclass2>)';

when superclass2 is the same as superclass1 ?

 

Is there a possibility to achieve that?

 

Thanks for your help.

Best regards

Axel

 

 

Re: [Rdfapi-php-interest] How to avoid duplicates rdf entities?

[Michele P. <mic...@gm...>]

Hey everybody,

I solved the issue so I thought someone else could have benefited from this.

The problem was that every time I was referencing to a resource, this was
created using the RDF:ID construct. Which is ok, as far as the resource is
not mentioned anymore using the same RDF:iD construct. Which for some
reasons was not happening .......The W3c RDF specs say:

"So for example if rdf:ID="name", that would be equivalent to
rdf:about="#name". rdf:ID provides an additional check since the same
*name*can only appear once in the scope of an
xml:base value (or document, if none is given) [...]"

My knowledge of RAP is limited, but for some reasons when the namespace was
set, it kept creating RDF:ID references irrespectively of whether it wasnt
the first time the resource is mentioned. And subsequently the RDF validator
was throwing an error......After a few trials I realized that the source of
the error was the  BASEURI declaration at the beginning:

$Model->setBaseURI(COHERE_NS);

once I got rid of that and started using full uris when creating new
Resources, the output was using RDF:ABOUT and thus it validates too.

rdf:About = rdf:about="http://cohere.......website_13710..................."

instead of the previous

rdf:ID="website_13710........"

does it make sense to anybody?

mik

On Wed, Apr 2, 2008 at 2:01 PM, Michele Pasin <mic...@gm...>
wrote:

> Hey Tom,
>
> sorry about the 'node' class, i'm so used to it I don't find it confusing
> anymore. So here's a simplified example in PHP, which you can easily run by
> yourself. Basically all I'm trying to write is 3 triples as follows:
>
> ($ID ---> rdf:TYPE -----> "http://cohereweb.net/ontology/cohere.owl#node")
> ($authorID ---> rdf:TYPE -----> "
> http://cohereweb.net/ontology/cohere.owl#cohere_user")
> ($ID ---> ""http://cohereweb.net/ontology/cohere.owl#has_creator" ----->
> $name)
>
>
> And here's the code:
> ........................................
> ....................
>

Re: [Rdfapi-php-interest] (no subject)

[Martin S. <ma...@ma...>]

On Thu, Apr 17, 2008 at 4:12 AM,  <Kar...@gm...> wrote:
> I want to develop an application to execute SPARQL queries in order to find resources according to user specific queries. For that i need to integrate the user interface with a SPARQL engine. Can anyone help me suggestions how i could integrate the user interface with a SPARQL engine?

I think the most difficult part of introducing the semantic web to the
users is the interface. Sometimes I think the interface should be as
specialized as possible and hide the interesting/macabre power of the
SW to the user and do the magic in the backend. Sometimes I'm sure we
need to teach users SPARQL :)

In dbpedia.org / online access you'll find some examples. I would like
to see other interfaces, too

[Rdfapi-php-interest] Intergrating User-Inferface with a SPARQL engine

[<Kar...@gm...>]

I want to develop an application to execute SPARQL queries in order to find resources according to user specific queries. For that i need to integrate the user interface with a SPARQL engine. Can anyone help me suggestions how i could integrate the user interface with a SPARQL engine?
-- 
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[Rdfapi-php-interest] (no subject)

[<Kar...@gm...>]

I want to develop an application to execute SPARQL queries in order to find resources according to user specific queries. For that i need to integrate the user interface with a SPARQL engine. Can anyone help me suggestions how i could integrate the user interface with a SPARQL engine?
-- 
Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! 
Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer

[Rdfapi-php-interest] LOD Triplification Challenge

[Sören A. <au...@in...>]

Hi all,

Together with this years I-Semantics conference [1] we are organizing a
Linking Open Data Triplification Challenge.

The challenge aims at expediting the process of revealing and exposing
structured (relational) representations, which already back most of the
existing Web sites, as well as raising awareness in the Web Developer
community and showcasing best practices.

The challenge awards attractive prices (MacBook Air, EeePC, iPod) to the
most innovative and promising semantifications. The prizes are kindly
sponsored by OpenLink Software [2], Punkt.NetServices [3] and InfAI [4].

More Information about the challenge can be found at:

http://triplify.org/Challenge

I think outreach to the Web developer communities (as intended with the
challenge) is really crucial right now to expedite the Semantic Web
deployment and I would be very excited if you support this effort - e.g.
by spreading the word and/or submitting to the challenge.

Best,

Sören

[1] http://www.i-semantics.at/
[2] http://www.openlinksw.com/
[3] http://www.punkt.at/
[4] http://infai.org/

--------------------------------------------------------------
Sören Auer, AKSW/Computer Science Dept., University of Leipzig
http://www.informatik.uni-leipzig.de/~auer,  Skype: soerenauer