Thanks Hugh for the quick reply!
Its quite weired, that the PHP odbc drive has such side-effects - I
thought the odbc client just forwards the query to the server and makes
the results it obtains from there available.
I somehow found a workaround last night - simply also selecting COUNT(*)
seems to return correct results:
SELECT DISTINCT ?o, COUNT(*) FROM <http://mytest.com> WHERE {?s a ?o}
I guess from that perspective I'm fine for now. Might however be still
worth fixing the bug for some upcomming Virtoso release, in case other
people have the same problem.
Best,
Sören
On 22.11.2010 2:18, Hugh Williams wrote:
Hi Sören,
I have installed the 1M BSBM data into a 64bit Windows Virtuoso 6.2 instance
and querying via the Conductor , isql or ODBC Directly I get the same 159
distinct rows returned:
$ /opt/virtuoso/bin/isql opluswinbuild:1111
Connected to OpenLink Virtuoso
Driver: 06.02.3128 OpenLink Virtuoso ODBC Driver
OpenLink Interactive SQL (Virtuoso), version 0.9849b.
Type HELP; for help and EXIT; to exit.
SQL> sparql SELECT DISTINCT ?o FROM<http://mytest> WHERE {?s a ?o};
o
VARCHAR
_______________________________________________________________________________
http://xmlns.com/foaf/0.1/Person
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductType1
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/ProductType
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductType2
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductType3
.
.
.
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductType150
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductType151
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/ProductFeature
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/Producer
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/Product
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/Vendor
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/Offer
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/Review
159 Rows. -- 958 msec.
SQL>
So the problem is not in the ODBC layer, but rather in the PHP ODBC interface
it seems.
In fact the problem seems to be with the "odbc_fetch_array()" function which is
fetching an array of results , as If I use the following sample PHP code which selects
one row at a time the correct 159 distinct rows are returned:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";>
<html xmlns="http://www.w3.org/1999/xhtml";>
<head>
<title>PHP ODBC test</title>
<style type="text/css">
body { padding: 1em; }
pre { padding: 0.3em; background-color: #e0e0e0; border: solid 1px silver }
</style>
</head>
<body>
<h1>Test PHP / ODBC / Virtuoso connection</h1>
<hr />
<pre>
<?php
ini_set("odbc.default_cursortype", "0");
$con=odbc_connect("Local Virtuoso", "dba", "dba");
if($con) {
printf("<p>Connected [%s].\n</p>\n", $con);
$query="sparql SELECT DISTINCT ?o FROM<http://mytest> WHERE {?s a ?o}";
print "Executing query [$query]<br />\n";
$rs = odbc_exec($con, $query);
$err=odbc_errormsg($con);
print "Current error state: [$err]<br />\n";
print "Results:<br />\n";
odbc_result_all($rs, "border=2");
odbc_close($con);
} else {
print "<p>Failed to connect!</p>\n";
}
?>
?>
<hr />
</body>
</html>
Lifted from http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtuosoPHP
documentation.
I shall look into why the "odbc_fetch_array()" function is problematic in the
morning ...
Best Regards
Hugh Williams
Professional Services
OpenLink Software
Web: http://www.openlinksw.com
Support: http://support.openlinksw.com
Forums: http://boards.openlinksw.com/support
Twitter: http://twitter.com/OpenLink
On 21 Nov 2010, at 22:09, Sören Auer wrote:
Hi all,
I have a problem with a SPARQL query using the DISTINCT feature.
I installed the commercial Virtuoso 6.2 distribution for Windows.
In order to run some experiments, I loaded the 1M BSBM data [1].
When I run the following query in conductor I get the correct results:
SELECT DISTINCT ?o FROM<http://mytest.com> WHERE {?s a ?o}
However, when running the same query from a hosted PHP script, the
results are not distinct anymore and I also get only a small subset:
<?php
$c=odbc_connect("Local Virtuoso",'dba','dba');
$r=odbc_exec($c,'sparql SELECT DISTINCT ?o FROM<http://mytest.com>
WHERE {?s a ?o}');
while($row=odbc_fetch_array($r))
print_r($row);
?>
What's the problem? How can it be that I get different results from
conductor and when submitting a query via ODBC? Or am I doing something
wrong?
Best,
Sören
[1]
http://www4.wiwiss.fu-berlin.de/bizer/BerlinSPARQLBenchmark/datasets/qualification.ttl.gz
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