When I do not use the subselect and write the query this way:
String queryString1 =
"PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>"+
"PREFIX cv:<
http://www.semanticweb.org/toshiba/ontologies/2017/3/untitled-ontology-6#>"+
"INSERT {"+
" ?ass cv:recorded_speed ?avg"+
"}"+
"WHERE {"+
"SELECT (AVG(?speed) AS ?avg) {"+
"?v cv:vehicleSpeed ?speed;"+
" cv:Vehicle_Road ?r ;"+
"?ass cv:avgSpeedSensor_Infrastructue ?r ."+
"}"+ "GROUP BY ?r ?ass"+
"}";
The code generates the error below when it tries to execute the update
action:
Exception in thread "main" org.apache.jena.query.QueryParseException:
Encountered " <VAR1> "?r "" at line 1, column 299.
Was expecting one of:
"values" ...
"graph" ...
"optional" ...
"minus" ...
"bind" ...
"service" ...
"filter" ...
"{" ...
"}" ...
";" ...
"," ...
"." ...
When I researched these options under "Was expecting one of:", I did not
find one of those options that would fit my query.
I need this line: "?ass cv:avgSpeedSensor_Infrastructue ?r ." to ensure
that the sensor is attached to the road on which the car is on.
I group by ?r to try to ensure that the grouping is per road as well. But I
think you have a point, and I should group by the sensor as well.
Note: when I write the " cv:Vehicle_Road ?r ;"+ line with a full stop
instead of a full stop the error goes away, but still, nothing happens in
the owl file. Meaning, the new tuple is not added either. (I am a bit
confused as to when to put a ";" and when to put a "." I believe, as far as
my understanding goes, when I put a "." in the end of the
" cv:Vehicle_Road ?r " the error goes away because the last line "?ass
cv:avgSpeedSensor_Infrastructue ?r ." is ignored in the first place. could
you confirm or negate that?)
Your help is truly much appreciated.
On Fri, Jun 9, 2017 at 2:30 PM, Lorenz Buehmann <
[email protected]> wrote:
> There was some formatting issue in my previous mail.
>
> What I was wondering the need for grouping by ?r instead of ?ass.
>
> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
> PREFIX cv:
> <http://www.semanticweb.org/toshiba/ontologies/2017/3/untitled-ontology-6#
> >
>
> INSERT {
> ?ass cv:recorded_speed ?avg .
> }
> WHERE
> { SELECT ?ass (AVG(?speed) AS ?avg)
> WHERE
> { ?v cv:vehicleSpeed ?speed ;
> cv:Vehicle_Road ?r .
> ?ass cv:avgSpeedSensor_Infrastructue ?r
> }
> GROUP BY ?r ?ass
> }
>
>
>
> On 09.06.2017 16:29, Lorenz Buehmann wrote:
> > That is your query:
> >
> > PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
> > PREFIX cv:
> > <http://www.semanticweb.org/toshiba/ontologies/2017/3/
> untitled-ontology-6#>
> >
> > INSERT {
> > ?ass cv:recorded_speed ?avg .
> > }
> > WHERE
> > { SELECT (AVG(?speed) AS ?avg)
> > WHERE
> > { ?v cv:vehicleSpeed ?speed ;
> > cv:Vehicle_Road ?r
> > { SELECT ?r
> > WHERE
> > { ?ass cv:avgSpeedSensor_Infrastructue ?r }
> > }
> > }
> > GROUP BY ?r
> > }
> >
> > The problem is that you use for what ever reason a sub-SELECT to get the
> > ?ass value. But this value is not propagated to the outer query, thus,
> > it's not bound to the INSERT part.
> >
> > Why not do it like here (note, I dPREFIX rdf:
> > <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
> > PREFIX cv:
> > <http://www.semanticweb.org/toshiba/ontologies/2017/3/
> untitled-ontology-6#>
> >
> > INSERT {
> > ?ass cv:recorded_speed ?avg .
> > }
> > WHERE
> > { SELECT ?ass (AVG(?speed) AS ?avg)
> > WHERE
> > { ?v cv:vehicleSpeed ?speed ;
> > cv:Vehicle_Road ?r .
> > ?ass cv:avgSpeedSensor_Infrastructue ?r
> > }
> > GROUP BY ?r ?ass
> > }on't know why you group by ?r instead of ?ass, thus, added both):
> >
> >
> >
> >
> > On 09.06.2017 14:22, Aya Hamdy wrote:
> >> Didn't know attachments are not allowed.
> >> This is a gist of the three files.
> >> https://gist.github.com/AyazzHamdy/faa14ebf46b0fe32689edc808dbf85d9
> >>
> >> The code files are minimalist as you can see on the gist. Only the
> query is
> >> included and everything else is removed. I wanted to attach them as
> files
> >> to avoid clutter in the email. I believe things are more organized this
> way.
> >>
> >> The problem is in b.java file. The c.java file is just to prove that the
> >> individual parts of the query work together. And the OWL file is the one
> >> generated by Protege. It has no problems, but I have removed anything
> that
> >> is not needed for this specific query.
> >>
> >> I have also attached a file called "ont.owl (full)" which has the full
> >> ontology in case it is needed (which I think it is not needed, but just
> in
> >> case I misunderstand).
> >>
> >> Regards,
> >>
> >> On Fri, Jun 9, 2017 at 8:47 AM, Andy Seaborne <[email protected]> wrote:
> >>
> >>> Attachments don't get through to this list.
> >>>
> >>> Put them in a pastebin or guithub gist.
> >>>
> >>> However, if they are so large that inlining email in plain text is
> >>> impractical, than it suggests they are not minimal.
> >>>
> >>> Andy
> >>>
> >>>
> >>>
> >>> On 09/06/17 07:06, Lorenz Buehmann wrote:
> >>>
> >>>> You forgot the attachments...
> >>>>
> >>>>
> >>>> On 09.06.2017 03:02, Aya Hamdy wrote:
> >>>>
> >>>>> Attached is a file of my code and my ontology which I have imported
> on
> >>>>> Eclipse.
> >>>>>
> >>>>> I have finally fixed the null values issue. I am not sure if I
> >>>>> understood the cause of the nulls correctly. However, it got fixed
> >>>>> when I used a different way of making the ResultSet as shown below:
> >>>>>
> >>>>> Query query = QueryFactory.create(queryString1);
> >>>>> QueryExecution qexec= QueryExecutionFactory.create(query,
> >>>>> ontologyModel);
> >>>>> ResultSet results=qexec.execSelect();
> >>>>> ResultSetFormatter.out(System.out, results, query);
> >>>>> qexec.close();
> >>>>> I am including this bit of code here in case this helps someone else
> >>>>> in the future cause I could not find it easily. It can be found in
> >>>>> context in the attached c.java file.
> >>>>>
> >>>>> However, the original bigger problem still persists. The insert
> SPARQL
> >>>>> query still does not result in inserting the new desired subject
> >>>>> predicate object triple. No errors are generated which is I suppose a
> >>>>> good thing, but when I print the ontology after running the query, I
> >>>>> can see that the new triples are not added.
> >>>>>
> >>>>> Attached is the owl file and the java file (b.java). I have added
> >>>>> explanatory comments in the java file hoping to clarify what I am
> >>>>> trying to do here.
> >>>>>
> >>>>> Also, hoping to clarify matters a bit more, I have two average speed
> >>>>> sensors (speedSensor1 and speedSensor2) and I have two vehicles
> >>>>> (vehicle1 and vehicle2). speedSensor1 is attached to Road1 and
> >>>>> speedSensor2 is attached to Road2. vehicle1 is located on Road1 with
> >>>>> vehicleSpeed of 0 and vehicle2 is located on Road2 with vehicleSpeed
> >>>>> of 50. Only one vehicle is modeled to be located on each road in an
> >>>>> attempt to simplify things for now.
> >>>>>
> >>>>> The goal is to calculate the average of speeds of all vehicles on
> >>>>> road1 and assign it as the value of the object property called
> >>>>> recorded_speed of the speed sensor attached to the road which the
> >>>>> vehicles are on. Consequently, based on my modeling, after running
> >>>>> the query, speedSensor1 should have recorded_speed of 0 (since only
> >>>>> vehicle1 is on road1 to which speedSensor1 is attached and vehicle1
> >>>>> has speed of 0) and speedSensor2 should have recorded_speed of 50
> >>>>> (since only vehicle2 is on road2 to which speedSensor2 is attached
> and
> >>>>> vehicle2 has speed of 50).
> >>>>>
> >>>>> Also, attached is another java file (c.java) that has the results of
> >>>>> me breaking down the big query in b.java.
> >>>>> My suspicion is that the part where I am trying to invoke the insert
> >>>>> query is not working, but the way I built is based on StackOverflow
> >>>>> and it was supposedly working fine, so I am not sure what I am
> missing.
> >>>>>
> >>>>> Hope this gives you a picture of what is going on and hope you can
> >>>>> help me understand why I cannot get the query to update the ontology.
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Thu, Jun 8, 2017 at 5:29 PM, Lorenz Buehmann
> >>>>> <[email protected]
> >>>>> <mailto:[email protected]>> wrote:
> >>>>>
> >>>>> If results are bound it can't be a null value. Please show your
> >>>>> updated
> >>>>> code.
> >>>>>
> >>>>>
> >>>>> On 07.06.2017 14:58, Aya Hamdy wrote:
> >>>>> > Sorry about the x, It was a stupid mistake. But it is nit the
> >>>>> cause of the
> >>>>> > null. When I fixed it, the results of even the simplest
> queries
> >>>>> are still
> >>>>> > nulls.
> >>>>> >
> >>>>> > The code is not generating errors though, it is not generating
> >>>>> the proper
> >>>>> > results ...
> >>>>> >
> >>>>> > On Tue, Jun 6, 2017 at 9:13 AM, Andy Seaborne <
> [email protected]
> >>>>> <mailto:[email protected]>> wrote:
> >>>>> >
> >>>>> >>
> >>>>> >> On 06/06/17 00:26, Aya Hamdy wrote:
> >>>>> >>
> >>>>> >>> Ok. That sounds reasonable so I will work on breaking down
> my
> >>>>> chain of
> >>>>> >>> thought into smaller pieces. Thank you so much.
> >>>>> >>>
> >>>>> >>> I saw an example online where the query syntax is written
> as a
> >>>>> string on
> >>>>> >>> Jena. so my query now looks like this:
> >>>>> >>>
> >>>>> >> Use
> >>>>> >>
> >>>>> >> String.join("\n"
> >>>>> >> , "PREFIX rdf:<http://www.w3.org/1999/
> 02/22-rdf-syntax-ns#
> >>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#>>"
> >>>>> >> , "PREFIX rdf:<http://www.w3.org/1999/
> 02/22-rdf-syntax-ns#
> >>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#>>"
> >>>>> >> , "INSERT {",
> >>>>> >> ...
> >>>>> >> , "}"
> >>>>> >> );
> >>>>> >>
> >>>>> >> then you will have newlines in the string and parser errors
> >>>>> will have
> >>>>> >> line+column numbers that are useful.
> >>>>> >>
> >>>>> >> Andy
> >>>>> >>
> >>>>> >>
> >>>>> >>
> >>>>> >>> String queryString=
> >>>>> >>> "PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#
> >>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#>>"+
> >>>>> >>> "PREFIX cv:<
> >>>>> >>>
> >>>>> http://www.semanticweb.org/toshiba/ontologies/2017/3/untitl
> >>>>> ed-ontology-6#
> >>>>> <http://www.semanticweb.org/toshiba/ontologies/2017/3/untit
> >>>>> led-ontology-6#>
> >>>>> >>>> "+
> >>>>> >>> "insert {"+
> >>>>> >>> " ?ass cv:recorded_speed ?avg"+
> >>>>> >>> "}"+
> >>>>> >>> "WHERE {"+
> >>>>> >>> "SELECT (AVG(?speed) AS ?avg) "+
> >>>>> >>> "where{"+
> >>>>> >>> " ?v rdf:type cv:Vehicle ;"+
> >>>>> >>> "cv:vehicleSpeed ?speed;"+
> >>>>> >>> " cv:Vehicle_Road ?r;"+
> >>>>> >>> "{"+
> >>>>> >>>
> >>>>> >>> "SELECT ?r"+
> >>>>> >>> "where{"+
> >>>>> >>>
> >>>>> >>> "?ass rdf:type cv:Avg_Speed_Sensor;"+
> >>>>> >>> " cv:avgSpeedSensor_Infrastructure ?r"+
> >>>>> >>> "}"+
> >>>>> >>> "}"+
> >>>>> >>>
> >>>>> >>>
> >>>>> >>>
> >>>>> >>> "}"+"GROUP By ?ass ?avg ?r"+
> >>>>> >>> "}";
> >>>>> >>>
> >>>>> >>> Then, also based on my research, I feed the query string
> into
> >>>>> the parser
> >>>>> >>> and output the model.
> >>>>> >>> UpdateAction.parseExecute( queryString, ontologyModel );
> >>>>> >>> ontologyModel.write( System.out, "TTL" );
> >>>>> >>> I encountered many errors but managed to get rid of them
> all.
> >>>>> However,
> >>>>> >>> based on the output, nothing has changed. speedSensor1 and
> >>>>> speedSensor2
> >>>>> >>> do
> >>>>> >>> not have the recorded_speed property added.
> >>>>> >>>
> >>>>> >>> Of course, I tried debugging, but I could not get any
> >>>>> understanding of the
> >>>>> >>> problem.
> >>>>> >>>
> >>>>> >>>
> >>>>> >>> I tried breaking the query down to smaller bits right down
> to
> >>>>> doing a
> >>>>> >>> simple select on vehicles:
> >>>>> >>>
> >>>>> >>> String query1=
> >>>>> >>> "PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#
> >>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#>>"+
> >>>>> >>> "PREFIX cv:<
> >>>>> >>>
> >>>>> http://www.semanticweb.org/toshiba/ontologies/2017/3/untitl
> >>>>> ed-ontology-6#
> >>>>> <http://www.semanticweb.org/toshiba/ontologies/2017/3/untit
> >>>>> led-ontology-6#>
> >>>>> >>>> "+
> >>>>> >>> "Select ?v"+
> >>>>> >>> "where {"+
> >>>>> >>> "?v cv:vehicleSpeed ?speed."+
> >>>>> >>> "}";
> >>>>> >>>
> >>>>> >>> Query query = QueryFactory.create(query1);
> >>>>> >>> QueryExecution qexec= QueryExecutionFactory.create(query,
> >>>>> ontologyModel);
> >>>>> >>> try{
> >>>>> >>> ResultSet results=qexec.execSelect();
> >>>>> >>> while(results.hasNext()){
> >>>>> >>> QuerySolution soln=results.nextSolution();
> >>>>> >>> org.apache.jena.rdf.model.Literal name =
> soln.getLiteral("x");
> >>>>> >>> System.out.println(name);
> >>>>> >>> }
> >>>>> >>> }finally{
> >>>>> >>> qexec.close();
> >>>>> >>> }
> >>>>> >>> But everything I have tried yields in the result "null".
> >>>>> >>>
> >>>>> >>> Can you give me pointers on how I should go about trying to
> >>>>> figure out the
> >>>>> >>> problem with the insert function?
> >>>>> >>> Sorry if my questions are too naive, but I am trying to
> grasp
> >>>>> the concepts
> >>>>> >>> as much as possible.
> >>>>> >>>
> >>>>> >>> Best Regards,
> >>>>> >>> Aya
> >>>>> >>>
> >>>>> >>>
> >>>>> >>>
> >>>>> >>>
> >>>>> >>> On Mon, Jun 5, 2017 at 8:32 PM, Andy Seaborne <
> [email protected]
> >>>>> <mailto:[email protected]>> wrote:
> >>>>> >>>
> >>>>> >>> Then find the sensor of interest, and all cars on that given
> >>>>> road.
> >>>>> >>>> GROUP BY the speed sensor, and the AVG is that of calls on
> >>>>> that given
> >>>>> >>>> road.
> >>>>> >>>>
> >>>>> >>>> The way to develop complex queris is to write simple parts,
> >>>>> then combine
> >>>>> >>>> them.
> >>>>> >>>>
> >>>>> >>>> Andy
> >>>>> >>>>
> >>>>> >>>>
> >>>>> >>>> On 05/06/17 16:46, Aya Hamdy wrote:
> >>>>> >>>>
> >>>>> >>>> The goal is not to calculate the avg speed of a car. It is
> >>>>> rather to
> >>>>> >>>>> compute the avg speed of all the cars on a given road and
> >>>>> assign that
> >>>>> >>>>> computed average as the reading of the average speed
> sensot
> >>>>> attached to
> >>>>> >>>>> that road.
> >>>>> >>>>>
> >>>>> >>>>> Sorry if my wording is causing confusion.
> >>>>> >>>>>
> >>>>> >>>>> On Jun 5, 2017 5:12 PM, "Lorenz Buehmann" <
> >>>>> >>>>> [email protected]
> >>>>> <mailto:[email protected]>> wrote:
> >>>>> >>>>>
> >>>>> >>>>> No, why do you think so? ?v is the variable that gets
> >>>>> assigned a vehicle
> >>>>> >>>>>
> >>>>> >>>>>> for which you compute the avg speed.
> >>>>> >>>>>>
> >>>>> >>>>>> <Instance> should be ?v, i.e. you have to group by it and
> >>>>> select it
> >>>>> >>>>>>
> >>>>> >>>>>> INSERT {
> >>>>> >>>>>>
> >>>>> >>>>>> ?v :avgSpeed ?avg
> >>>>> >>>>>>
> >>>>> >>>>>> } WHERE {
> >>>>> >>>>>>
> >>>>> >>>>>> SELECT ?v (AVG(?speed) AS ?avg) {
> >>>>> >>>>>>
> >>>>> >>>>>> ....
> >>>>> >>>>>>
> >>>>> >>>>>> } GROUP BY ?v
> >>>>> >>>>>>
> >>>>> >>>>>> }
> >>>>> >>>>>>
> >>>>> >>>>>>
> >>>>> >>>>>> On 05.06.2017 17:03, Aya Hamdy wrote:
> >>>>> >>>>>>
> >>>>> >>>>>> Hello,
> >>>>> >>>>>>> I will try to explain with examples. I have generated my
> >>>>> ontology from
> >>>>> >>>>>>> Protege and converted it to turtle syntax via an online
> >>>>> tool.
> >>>>> >>>>>>>
> >>>>> >>>>>>> *I have a class for average speed sensors:*
> >>>>> >>>>>>>
> >>>>> >>>>>>> ###
> >>>>> >>>>>>> http://www.semanticweb.org/toshiba/ontologies/2017/3/
> >>>>> <http://www.semanticweb.org/toshiba/ontologies/2017/3/>
> >>>>> >>>>>>>
> >>>>> >>>>>>> untitled-ontology-6#Avg_Speed_Sensor
> >>>>> >>>>>>
> >>>>> >>>>>>> untitled-ontology-6:Avg_Speed_Sensor rdf:type
> owl:Class ;
> >>>>> >>>>>>>
> >>>>> >>>>>>> rdfs:subClassOf
> >>>>> >>>>>>> untitled-ontology-6:Sensor ,
> >>>>> >>>>>>>
> >>>>> >>>>>>> untitled-ontology-6:Speed_Sensor .
> >>>>> >>>>>>>
> >>>>> >>>>>>> *and a class for vehicles:*
> >>>>> >>>>>>> ###
> >>>>> >>>>>>> http://www.semanticweb.org/toshiba/ontologies/2017/3/
> >>>>> <http://www.semanticweb.org/toshiba/ontologies/2017/3/>
> >>>>> >>>>>>>
> >>>>> >>>>>>> untitled-ontology-6#Vehicle
> >>>>> >>>>>>
> >>>>> >>>>>>> untitled-ontology-6:Vehicle rdf:type owl:Class .
> >>>>> >>>>>>>
> >>>>> >>>>>>> *The vehicle class has a property called vehicleSpeed:*
> >>>>> >>>>>>> ###
> >>>>> >>>>>>> http://www.semanticweb.org/toshiba/ontologies/2017/3/
> >>>>> <http://www.semanticweb.org/toshiba/ontologies/2017/3/>
> >>>>> >>>>>>>
> >>>>> >>>>>>> untitled-ontology-6#vehicleSpeed
> >>>>> >>>>>>
> >>>>> >>>>>>> untitled-ontology-6:vehicleSpeed rdf:type
> >>>>> owl:DatatypeProperty ;
> >>>>> >>>>>>>
> >>>>> >>>>>>> rdfs:domain
> >>>>> >>>>>>> untitled-ontology-6:Vehicle
> >>>>> >>>>>>>
> >>>>> >>>>>>> ;
> >>>>> >>>>>>
> >>>>> >>>>>>> rdfs:range
> xsd:integer .
> >>>>> >>>>>>>
> >>>>> >>>>>>> *The avg speed sensor class has a property called
> >>>>> recorded_speed:*
> >>>>> >>>>>>>
> >>>>> >>>>>>> ###
> >>>>> >>>>>>> http://www.semanticweb.org/toshiba/ontologies/2017/3/
> >>>>> <http://www.semanticweb.org/toshiba/ontologies/2017/3/>
> >>>>> >>>>>>>
> >>>>> >>>>>>> untitled-ontology-6#recorded_speed
> >>>>> >>>>>>
> >>>>> >>>>>>> untitled-ontology-6:recorded_speed rdf:type
> >>>>> owl:DatatypeProperty ;
> >>>>> >>>>>>>
> >>>>> >>>>>>> rdfs:domain
> >>>>> >>>>>>>
> >>>>> >>>>>>> untitled-ontology-6:Sensor ,
> >>>>> >>>>>>
> >>>>> >>>>>>> untitled-ontology-6:Speed_Sensor ;
> >>>>> >>>>>>>
> >>>>> >>>>>>> rdfs:range
> xsd:integer
> >>>>> .
> >>>>> >>>>>>>
> >>>>> >>>>>>> The recorded speed by the avg speed sensor allocated to
> a
> >>>>> specific
> >>>>> >>>>>>> road
> >>>>> >>>>>>>
> >>>>> >>>>>>> is
> >>>>> >>>>>> the average of the vehicleSpeeds of the vehicles on that
> >>>>> specific road,
> >>>>> >>>>>>> where the avg speed sensor class has a property called
> >>>>> >>>>>>> avgSpeedSensor_Infrastructure and the vehicle has a
> >>>>> property called
> >>>>> >>>>>>> Vehicle_Road.
> >>>>> >>>>>>>
> >>>>> >>>>>>> I have two vehicle instances: Vehicle1 and Vehicle2; and
> >>>>> two sensor
> >>>>> >>>>>>> instances: SpeedSensor1 and SpeedSensor2.
> >>>>> >>>>>>>
> >>>>> >>>>>>> Is it clearer now or just confusing?
> >>>>> >>>>>>>
> >>>>> >>>>>>> so I am guessing following your guide it would be
> >>>>> something like:
> >>>>> >>>>>>>
> >>>>> >>>>>>> INSERT {
> >>>>> >>>>>>> <instance> :avgSpeed ?avg
> >>>>> >>>>>>> }
> >>>>> >>>>>>> WHERE {
> >>>>> >>>>>>> SELECT (AVG(?speed) AS ?avg) {
> >>>>> >>>>>>> ?v rdf:type :Vehicle ;
> >>>>> >>>>>>> :vehicleSpeed ?speed;
> >>>>> >>>>>>> : Vehicle_Road ?r;
> >>>>> >>>>>>> ?avs rdf:type :Avg_Speed_Sensor;
> >>>>> >>>>>>> :avgSpeedSensor_Infrastructure ?r
> >>>>> >>>>>>>
> >>>>> >>>>>>> }
> >>>>> >>>>>>> }
> >>>>> >>>>>>>
> >>>>> >>>>>>> But the value of the <instance> should come from
> reading
> >>>>> the file,
> >>>>> >>>>>>>
> >>>>> >>>>>>> right?
> >>>>> >>>>>>
> >>>>> >>>>>>> On Sun, Jun 4, 2017 at 9:04 PM, Andy Seaborne
> >>>>> <[email protected] <mailto:[email protected]>>
> >>>>> >>>>>>> wrote:
> >>>>> >>>>>>>
> >>>>> >>>>>>>
> >>>>> >>>>>>> On 04/06/17 18:47, Aya Hamdy wrote:
> >>>>> >>>>>>>> Hello,
> >>>>> >>>>>>>>
> >>>>> >>>>>>>>> I wanted to add a property called avgSpeed to an
> >>>>> instance of a class
> >>>>> >>>>>>>>> called
> >>>>> >>>>>>>>> FlowSensor. This property should be the average of the
> >>>>> values of the
> >>>>> >>>>>>>>> property vehicleSpeed attached to instances of the
> class
> >>>>> Vehicle.
> >>>>> >>>>>>>>>
> >>>>> >>>>>>>>> I read that SPARQL update allows doing this. However,
> I
> >>>>> cannot reach
> >>>>> >>>>>>>>>
> >>>>> >>>>>>>>> the
> >>>>> >>>>>> syntax for doing the* averaging of values* or for
> building
> >>>>> the *SPARQL
> >>>>> >>>>>>>> Update *query using jena with eclipse on the jena
> website.
> >>>>> >>>>>>>>> If Jena indeed supports doing what I intend to do then
> >>>>> can someone
> >>>>> >>>>>>>>>
> >>>>> >>>>>>>>> point
> >>>>> >>>>>> out some sources to guide me in my attempt?
> >>>>> >>>>>>>>> Best Regards,
> >>>>> >>>>>>>>> Aya
> >>>>> >>>>>>>>>
> >>>>> >>>>>>>>>
> >>>>> >>>>>>>>> Calculate the average in a nested select so somethign
> >>>>> like (you'll
> >>>>> >>>>>>>>>
> >>>>> >>>>>>>> have
> >>>>> >>>>>>>>
> >>>>> >>>>>>>> to
> >>>>> >>>>>> fix this up):
> >>>>> >>>>>>>> INSERT {
> >>>>> >>>>>>>> <instance> :avgSpeed ?avg
> >>>>> >>>>>>>> }
> >>>>> >>>>>>>> WHERE {
> >>>>> >>>>>>>> SELECT (AVG(?speed) AS ?avg) {
> >>>>> >>>>>>>> ?v rdf:type :Vehicle ;
> >>>>> >>>>>>>> :vehicleSpeed ?speed
> >>>>> >>>>>>>> }
> >>>>> >>>>>>>> }
> >>>>> >>>>>>>>
> >>>>> >>>>>>>> By the way - it is better to more concrete in your
> >>>>> description -
> >>>>> >>>>>>>> actual
> >>>>> >>>>>>>> data for example.
> >>>>> >>>>>>>>
> >>>>> >>>>>>>>
> >>>>> >>>>>>>>
> >>>>> >>>>>>
> >>>>>
> >>>>>
> >>>>>
>
>
