RE: [ojb-users] references

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Hi Steven,

I recently ported an application of mine from Castor to OJB and am glad
I did.  However, I also had problems getting things to work at first. 
I spent a lot of time stepping through OJB with a debugger just to find
out that it was my fault, I didn't read the docs carefully enough.

Anyway, one BIG THING you can do diagnose problems (and I don't know if
this is in the docs or not) is to crank up the logging that OJB does.

In your ojb.properties file look for this line...

 ojb.broker.metadata.RepositoryXmlHandler.LogLevel=WARN

...and change it to this...

 ojb.broker.metadata.RepositoryXmlHandler.LogLevel=DEBUG

Doing that will make it easier to see if there are syntax problems in
your mapping file.  

Also, you can change this line...
 ojb.broker.accesslayer.SqlGenerator.LogLevel=WARN
...to this...
 ojb.broker.accesslayer.SqlGenerator.LogLevel=DEBUG
...and this will make it easier to see if you've misspelled and DB
table or column names or to see how well the mapping is working.

ted stockwell

--- "Ebersole, Steven" <ste...@vi...> wrote:
> Trying not to sound pushy here, but as I mentioned in my first post I
> am
> considering moving from Castor over to OJB for the project on which I
> am
> currently working.  However, I am unable to get even simple reference
> relationships working.  Obviously I can't move the project over to
> this
> library if this is going to be the case.  But it seems others are
> getting
> this to work.
> 
> So I guess my question is now, should I even continue evaluating OJB?
>  I
> mean it has been almost a month since my original post, and I am
> still no
> closer to solving the issue and not a single person has been willing
> (or
> knowledgeable enough) to help.  I know this is open source and as
> such: 1) I
> could simply debug the library myself; 2) people contribute and help
> others
> as their time allows.  As for one, I am in the middle of a project
> myself
> and unfortunately cannot validate the time to spend troubleshooting a
> proposed library which may not even be used.  As for two, I
> understand the
> time constraints of others, but to wait one month for for a response
> on such
> a basic O/R-mapping requirement as relationships?
> 
> Also, as I have previously mentioned, the set-up and the
> implementation of
> this library are extremely promising (especially in the environment
> in which
> I was hoping to use it).  In short I want to use this product. 
> However, I
> cannot swap out Castor to OJB at this time because I do not feel
> confident
> enough in OJB's capibilities mainly because every test I have tried
> to run
> (above and beyond strict table-to-object) fails.
> 
> Please, please can anyone help with the below problem?  Anyone
> encountered
> it before?
> 
> Thanks in advance
> 
> 
> 
> ********************************************
> Steve Ebersole
> IT Integration Engineer
> Vignette Corporation 
> 512.741.4195
> 
> Visit http://www.vignette.com
> 
> ********************************************
> 
> 
> -----Original Message-----
> From: Ebersole, Steven [mailto:ste...@vi...]
> Sent: Monday, May 20, 2002 7:47 AM
> To: 'Thomas Mahler'; obj...@li...
> Subject: RE: [ojb-users] references
> 
> 
> Any ideas?
> 
> 
> ********************************************
> Steve Ebersole
> IT Integration Engineer
> Vignette Corporation 
> 512.741.4195
> 
> Visit http://www.vignette.com
> 
> ********************************************
> 
> 
> -----Original Message-----
> From: Ebersole, Steven [mailto:ste...@vi...]
> Sent: Wednesday, May 08, 2002 7:09 AM
> To: 'Thomas Mahler'; obj...@li...
> Subject: RE: [ojb-users] references
> 
> 
> Below is the exception I get.  I appears that the exception occurs
> when
> trying to resolve the reference to parent company when that fk column
> is
> null.  If I remove that reference descriptor, everything works.
> 
> Query from class com.vignette.it.apps.dbapi.domain.CompanyDO where
> comp_id=
> ?
> [DEFAULT] WARN: Please define a public constructor for class
> com.vignette.it.apps.dbapi.domain.CompanyDO
> with the following signature: (java.lang.Integer, java.lang.String,
> java.lang.Integer).
> It must initialize the classes persistent attributes. This is
> recommended to
> increase performance but it's not mandatory!
> [ojb.broker.singlevm.PersistenceBrokerImpl] ERROR: expected type:
> class
> com.vignette.it.apps.dbapi.domain.CompanyDO
> [ojb.broker.accesslayer.RsIterator] ERROR: null
> java.lang.ArrayIndexOutOfBoundsException
>         at
>
ojb.broker.metadata.ClassDescriptor.getFieldDescriptorByIndex(ClassDescripto
> r.java:263)
>         at
>
ojb.broker.metadata.ObjectReferenceDescriptor.getForeignKeyFieldDescriptors(
> ObjectReferenceDescriptor.java:242)
>         at
>
ojb.broker.metadata.ObjectReferenceDescriptor.getForeignKeyValues(ObjectRefe
> renceDescriptor.java:264)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getReferencedObject(PersistenceBro
> kerImpl.java:700)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.retrieveReferences(PersistenceBrok
> erImpl.java:517)
>         at
>
ojb.broker.accesslayer.RsIterator.getObjectFromResultSet(RsIterator.java:263
> )
>         at
> ojb.broker.accesslayer.RsIterator.next(RsIterator.java:145)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:900)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:966)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:1054)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:1041)
>         at TestOJBInstall.execute(TestOJBInstall.java:66)
>         at TestOJBInstall.main(TestOJBInstall.java:53)
> java.util.NoSuchElementException
>         at
> ojb.broker.accesslayer.RsIterator.next(RsIterator.java:154)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:900)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:966)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:1054)
>         at
>
ojb.broker.singlevm.PersistenceBrokerImpl.getCollectionByQuery(PersistenceBr
> okerImpl.java:1041)
>         at TestOJBInstall.execute(TestOJBInstall.java:66)
>         at TestOJBInstall.main(TestOJBIError occurred :
> java.util.NoSuchElementException
> nstall.java:53)
> 
> 
> 
> 
> 
> ********************************************
> Steve Ebersole
> IT Integration Engineer
> Vignette Corporation 
> 512.741.4195
> 
> Visit http://www.vignette.com
> 
> ********************************************
> 
> 
> -----Original Message-----
> From: Thomas Mahler [mailto:tho...@ho...]
> Sent: Friday, May 03, 2002 12:11 AM
> To: Ebersole, Steven
> Subject: Re: [ojb-users] references
> 
> 
> Hi Steven,
> 
> Ebersole, Steven wrote:
> 
> > I am looking at switching from Castor over to OJB as it looks
> really
> > promising in terms of its functionality (I especially love the use
> of
> > virtual proxies here).  I did have two questions come up from my
> initial
> > trials of OJB.
> > 
> > 1) Is it necessary to have both the foreign key and the foreign
> reference
> > mapped and present on the object?  
> 
> 
> depends on the navigibility between your persistent classes.
> If you want to navigate from the 1-side to the n-side only, you just 
> need a foreign key (and a ForeignKeyDescriptor).
> 
> If you want navigation from the n-side to the 1-side too, you'll also
> 
> need a reference attribute (and a ReferenceDecsriptor too).
> 
> In the examples, the relation between
> > Article and ProductGroup is the example From which I was working. 
> There,
> > Article has two attributes dealing with its relation to a
> ProductGroup,
> 
> 
> Yes, because we have navigation from ProductGroup to all its Articles
> 
> and from an Article to its associated ProductGroup.
> 
> 
> > productGroupId (which is the DB fk field) and productGroup (which
> is an
> > instance of the ProductGroup object to which productGroupId
> referes).  Is
> it
> > necessary to do this, or is there a way to have the Product object
> only
> know
> > about its related ProductGroup?
> 
> 
> No, because ProductGroup and Article have a 1:n relation the table 
> representaing Article entities *must* have a foreign key to identify
> the 
> associated ProductGroup.
> 
> 
> > 
> > 2) I mapped a relationship, uing my classes, similiar to the above
> > relationship (it is a company -> parent company relationship). 
> However, I
> > get exceptions if a particular company did not have a parent
> company (its
> > PRTN_COMP_ID column on the DB is NULL).  Is there something
> additional I
> > have to set up in the mapping to define that side of the
> relationship as
> > optional?  Below is the mapping I have for this:
> > 
> > 
> >     <ClassDescriptor id="2">
> >
> <class.name>com.vignette.it.apps.dbapi.domain.CompanyDO</class.name>
> >         <table.name>COMPANY</table.name>
> >         <FieldDescriptor id="1">
> >             <field.name>id</field.name>
> >             <column.name>COMP_ID</column.name>
> >             <jdbc_type>INTEGER</jdbc_type>
> >             <PrimaryKey>true</PrimaryKey>
> >         </FieldDescriptor>
> >          ...
> >         <FieldDescriptor id="5">
> >             <field.name>parentCompanyId</field.name>
> >             <column.name>PRNT_COMP_ID</column.name>
> >             <jdbc_type>INTEGER</jdbc_type>
> >         </FieldDescriptor>
> >         <ReferenceDescriptor id="1">
> >             <rdfield.name>parentCompany</rdfield.name>
> >  
> >
>
<referenced.class>com.vignette.it.apps.dbapi.domain.CompanyDO</referenced.cl
> > ass>
> >             <fk_descriptor_ids>5</fk_descriptor_ids>
> >         </ReferenceDescriptor>
> >    </ClassDescriptor>
> > 
> 
> 
> Your mapping seems OK. This must be an OJB bug! Can you provide me
> with 
> a full stacktrace ?
> 
> thanks,
> 
> Thomas
> 
> 
> > 
> > Thanks
> > 
> > 
> > 
> > 
> > ********************************************
> > Steve Ebersole
> > IT Integration Engineer
> > Vignette Corporation 
> > 512.741.4195
> > 
> > Visit http://www.vignette.com
> > 
> > ********************************************
> > 
> > _______________________________________________________________
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> > 
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