Andy,
Sorry about the attachments. I'm not sure why they were eaten. I've pasted
the two files into the email body below, along with the output.
I'm afraid that as soon as I retried my test program (with a couple of minor
changes) in light of your advice, I was unable to duplicate the behavior that I
thought I had observed. Rather, I found different, but still puzzling
behavior. I suspect I simply made a mistake previously. Here is a quick
summary of my experiment:
* I am comparing a numeric literal in a query to an integer literal in a model.
* The variables are:
- Memory model versus TDB model
- Comparison within a filter versus in the triple pattern itself
- Integer versus decimal
- Canonical versus non-canonical lexical form
* Complete results can be seen below, but the unexpected result is this: When
the literal in the query is in the triple pattern and is type decimal, then a
memory model produces a positive match, but a TDB model does not.
* I am using TDB 0.8.10 (and the Jena and ARQ that come with it).
Is this what you expect?
Thanks,
Ian
On Aug 12, 2011, at 5:03 AM, Andy Seaborne wrote:
> On 11/08/11 22:41, Ian Emmons wrote:
>> TDB experts,
>>
>> At [1], the TDB documentation indicates that TDB will regard
>> "47"^^xsd:integer and "47.0"^^xsd:decimal as the same value and match
>> them in a query. However, when I store the former and query for the
>> latter, TDB does not return the expected result.
>
> TDB stores the values of integer and decimal, but it does stil keep those two
> types part. The rules of XSD arithmetic try not to over promote datatypes
> e.g. integer + integer is integer.
>
> I guess "by query" you are putting the decimal directly in a graph pattern.
> They are the same value in FILTERs.
>
>> I've attached a small sample program and the .ttl file that it reads
>> so that you can reproduce the problem. My question is, what am I
>> doing wrong, here?
>
> The attachments are empty - and indeed the [1] link is in the second
> attachment. I can send you the raw source of the message I received if that
> helps.
>
> Andy
>
>> Thanks,
>>
>> Ian
>>
>> [1] http://jenawiki.hpl.hp.com/wiki/TDB/ValueCanonicalization
=================== Output ===================
Memory model: 47 as integer by triple pattern: 1 results
Memory model: +047 as integer by triple pattern: 1 results
Memory model: 47 as decimal by triple pattern: 1 results
Memory model: +047.0 as decimal by triple pattern: 1 results
Memory model: 47 as integer by filter: 1 results
Memory model: +047 as integer by filter: 1 results
Memory model: 47 as decimal by filter: 1 results
Memory model: +047.0 as decimal by filter: 1 results
TDB model: 47 as integer by triple pattern: 1 results
TDB model: +047 as integer by triple pattern: 1 results
TDB model: 47 as decimal by triple pattern: 0 results
TDB model: +047.0 as decimal by triple pattern: 0 results
TDB model: 47 as integer by filter: 1 results
TDB model: +047 as integer by filter: 1 results
TDB model: 47 as decimal by filter: 1 results
TDB model: +047.0 as decimal by filter: 1 results
=================== tempTestTDB.ttl ===================
@prefix eg: <http://example.com/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
eg:F0 rdfs:label "47"^^xsd:integer .
=================== ExampleTDB.java ===================
import java.io.File;
import java.io.InputStream;
import com.hp.hpl.jena.query.Query;
import com.hp.hpl.jena.query.QueryExecution;
import com.hp.hpl.jena.query.QueryExecutionFactory;
import com.hp.hpl.jena.query.QueryFactory;
import com.hp.hpl.jena.query.QuerySolution;
import com.hp.hpl.jena.query.ResultSet;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.tdb.TDBFactory;
import com.hp.hpl.jena.util.FileManager;
public class ExampleTDB {
private static enum QueryBy {
TRIPLE_PATTERN("triple pattern",
"PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>%n"
+ "SELECT ?x WHERE {%n"
+ " ?x ?y \"%1$s\"^^xsd:%2$s .%n"
+ "}"),
FILTER("filter",
"PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>%n"
+ "SELECT ?x WHERE {%n"
+ " ?x ?y ?z .%n"
+ " FILTER( ?z = \"%1$s\"^^xsd:%2$s )%n"
+ "}");
public final String _label;
public final String _queryFmt;
private QueryBy(String label, String queryFmt) {
_label = label;
_queryFmt = queryFmt;
}
}
public static void main(String[] args) throws Exception {
runQueries(getMemoryModel(), "Memory");
runQueries(getTdbModel(), "TDB");
}
private static Model getMemoryModel() {
Model model = ModelFactory.createDefaultModel();
InputStream in = FileManager.get().open("tempTestTDB.ttl");
model.read(in, "", "TURTLE");
return model;
}
private static Model getTdbModel() {
File tdbDir = new File("tempTestTDBData");
boolean needToLoadModel = !tdbDir.exists();
Model model = TDBFactory.createModel(tdbDir.getAbsolutePath());
if (needToLoadModel) {
InputStream in = FileManager.get().open("tempTestTDB.ttl");
model.read(in, "", "TURTLE");
}
return model;
}
private static void runQueries(Model model, String modelKind) {
runQuery(model, modelKind, QueryBy.TRIPLE_PATTERN, "integer", "47");
runQuery(model, modelKind, QueryBy.TRIPLE_PATTERN, "integer", "+047");
runQuery(model, modelKind, QueryBy.TRIPLE_PATTERN, "decimal", "47");
runQuery(model, modelKind, QueryBy.TRIPLE_PATTERN, "decimal", "+047.0");
runQuery(model, modelKind, QueryBy.FILTER, "integer", "47");
runQuery(model, modelKind, QueryBy.FILTER, "integer", "+047");
runQuery(model, modelKind, QueryBy.FILTER, "decimal", "47");
runQuery(model, modelKind, QueryBy.FILTER, "decimal", "+047.0");
}
private static void runQuery(Model model, String modelKind,
QueryBy by, String datatype, String lexicalForm) {
Query query = QueryFactory.create(String.format(
by._queryFmt, lexicalForm, datatype));
QueryExecution qe = QueryExecutionFactory.create(query, model);
int count = countQueryResults(qe.execSelect());
System.out.format(
"%1$6s model: %2$6s as %3$s by %4$-15s %5$d results%n",
modelKind, lexicalForm, datatype, (by._label + ":"), count);
}
private static int countQueryResults(ResultSet rs) {
int count = 0;
while (rs.hasNext()) {
@SuppressWarnings("unused")
QuerySolution qs = rs.next();
++count;
}
return count;
}
}
