jdbc-odbc ontop 4D

[Stéphane Curet]

Hello again,

After successfull tests with a mysql database, i'm trying to connect protégé/ontop width a 4D database, with ODBC.

I success to make a connection with jdbd-odbc, i can request in the mapping manager (but not into the mapping-assistant)

I create a simple mapping.

And when i try to run a sparql request, i obtain this error :


Quest was not initialized properly. This is generally indicates, connection problems or error during ontology or mapping pre-processing.

Original error message:
java.lang.NullPointerException

###################################################
##    Debugging information (for the authors)    ##
###################################################

    at it.unibz.krdb.obda.owlrefplatform.core.Quest.setupRepository(Quest.java:874)
    at it.unibz.krdb.obda.owlrefplatform.owlapi3.QuestOWL.prepareQuestInstance(QuestOWL.java:278)
    at it.unibz.krdb.obda.owlrefplatform.owlapi3.QuestOWL.prepareReasoner(QuestOWL.java:454)
    at it.unibz.krdb.obda.owlrefplatform.owlapi3.QuestOWL.<init>(QuestOWL.java:201)
    at it.unibz.krdb.obda.owlrefplatform.owlapi3.QuestOWLFactory.createReasoner(QuestOWLFactory.java:142)
    at org.protege.editor.owl.model.inference.ReasonerUtilities.createReasoner(ReasonerUtilities.java:21)
    at org.protege.editor.owl.model.inference.OWLReasonerManagerImpl$ClassificationRunner.ensureRunningReasonerInitialized(OWLReasonerManagerImpl.java:398)
    at org.protege.editor.owl.model.inference.OWLReasonerManagerImpl$ClassificationRunner.run(OWLReasonerManagerImpl.java:354)
    at java.lang.Thread.run(Unknown Source)

I test with success the same mapping with a same database in mysql.

Do you have any idea ? Is-it a 4D trouble and no protégé/ontop ?

cheers,

Stéphane

[Guohui Xiao]

Dear Stéphane,

Inside ontop, for each supported database, we need to implement some classes/methods for it.

Unfortunately Database 4D is not in the list we officially support. 

Actually we never worked with 4D so we cannot tell much at this moment.

May I ask in your scenario, what is advantage of 4D over MySQL?

Best regards,

Guohui

[Stéphane Curet]

Guohui, thank you for your answer that help me to go ahead !

I have to use 4D since the software I use here is in 4D. That's the technical constraint !

It seems a way to solve the trouble, is to ask 4D with http request. (there's a web server in 4D)

Is it possible to link Ontop with http to a database ? Is it possible to send http request with Ontop ?

Best regards,

Stéphane

[Guohui Xiao]

I see, we also have technical constraint. Sorry, as far as I can see, we don't have plan to support linking ontop without JDBC in the near future. 

 

Best regards,

Stéphane

[Stéphane Curet]

Guohui,

Thank you for the quick answer. It's clear, and it help me, even if there's no solution for instance.

Best regards,

Stéphane

[Martín Rezk]

Hi Stephane,
You might try to put Teiid on top of 4D, and then
connect ontop to Teiid.

http://teiid.jboss.org/

Let us know how it goes if you try.

cheers,

Martin.-

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[Stéphane Curet]

Guohui,

I precise that I use odbc client with 4D database, that mean normaly it's odbc !
With ontop, i use jdbc-odbc driver :
sun.jdbc.odbc.JdbcOdbcDriver
C:\Program Files\Java\jre7\lib\rt.jar

And after a good connection, if I try for example to use the mapping-assistant i see on the log :

[Thread-4] WARN  i.u.k.o.o.c.q.SQLAdapterFactory - WARNING: the specified driver doesn't correspond to any of the drivers officially supported by Ontop.

Are you sure there's nothing to do more with the jdbc-odbc driver ?

Martin,

Thank you very much for teiid ! I will look further. It's probably the good solution if jdbc-odbc driver is not efficient with odbc-4D.


Thank you very much to all.

Best regards,

Stéphane

[Guohui Xiao]

Dear Stéphane,

Thanks for the info, now I have a better understanding.
In theory, ontop can be extended to support jdbc-odbc driver by
implementing dedicated classes or methods.
If you or you team want to try to extend ontop, you are very welcome.
Currently, we do not have human resource to implement it.

I also noticed that the jdbc-obdc bridge is already removed from Java 8 [1].
It seems that jdbc-obdc bridge is an out-dated technology and ontop
will move to Java 8 eventually.
Do you really want to use jdbc-obdc ?

[1] http://stackoverflow.com/questions/22751071/jdbc-odbc-bridge-removed-in-java-8-what-is-the-best-alternative


Guohui

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Guohui Xiao

Faculty of Computer Science
Free University of Bozen-Bolzano
Piazza Domenicani, 3
I-39100 Bolzano-Bozen BZ, Italy

http://www.ghxiao.org

[Stéphane Curet]

Thanks Guohui !

I understand better too !
I think we will forget jdbc-odbc !

Now I will use Teiid !
And i will later give news here to explain how it runs.

Thank you very much for your quick answers and your help !

Best Regards,

Stéphane