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Re: [eclipselink-users] loading collection problem 
Hi Tom,

The DescriptorCustomizer is a workaround, right? So can we consider the
need for it a bug in EclipseLink? By adding this - we loose the ability
to switch persistency providers, which is a shame.

-J.

On Wed, 2008-04-23 at 20:18 +0200, Leon Derks wrote:
> Hi Tom,
> 
> I used an DescriptorCustomizer on Gear and that worked!
> Thanks!
> 
> Leon
> 
> Tom Ware wrote:
> > Hi Leon,
> >
> >   You will want to use a DescriptorCustomizer on Product.
> >
> > http://wiki.eclipse.org/Using_EclipseLink_JPA_Extensions_%28ELUG%29#Using_EclipseLink_JPA_Extensions_for_Customization_and_Optimization 
> >
> >
> >   In your descriptor customizer you'll be given a callback that 
> > includes a ClassDescriptor.
> >
> > http://wiki.eclipse.org/Configuring_a_Descriptor_%28ELUG%29#Configuring_a_Descriptor_Customizer_Class 
> >
> >
> >   You should call 
> > classDescriptor.getInheritancePolicy().setAlwaysUseOuterJoinForClassType(true) 
> >
> >
> > -Tom
> >
> > Leon Derks wrote:
> >> Hi Tom,
> >>
> >> Yes indeed, with the outer join syntax I get the correct result.
> >>
> >> What is the workaround for this?
> >>
> >> Leon
> >>
> >>
> >> Tom Ware wrote:
> >>> Hi Leon,
> >>>
> >>>   If you run slightly changed SQL do you get the correct results. 
> >>> (change t0.PRODUCT_TYPE = ? to use the outer join syntax - 
> >>> t0.PRODUCT_TYPE (+) = 'Gear')
> >>>
> >>>   If that change gives you better results, it likely points to a 
> >>> result that I can give you a workaround for.
> >>>
> >>>   The other thing you can try is to make your @JoinFetch on 
> >>> IndustrialFamily to use an OuterJoin
> >>>
> >>> @JoinFetch(JoinFetchType.OUTER)
> >>>
> >>> -Tom
> >>>
> >>> Leon Derks wrote:
> >>>> Hi Tom,
> >>>>
> >>>> Named query: select l from Lamp l left join fetch l.gears where 
> >>>> l.id = :lampId
> >>>>
> >>>> This is the SQL:
> >>>> SELECT t1.ID, t1.PRODUCT_TYPE, t1.CODE, t1.SHORT_CODE, t1.NAME, 
> >>>> t1.family_id, t0.ID, t0.PRODUCT_TYPE, t0.CODE, t0.SHORT_CODE, 
> >>>> t0.NAME, t0.family_id, t0.GEAR_TYPE, t2.ID, t2.CODE, t2.NAME, 
> >>>> t2.PROD_CAT FROM PLI_LAMP_GEAR t3, PLI.PLI_INDUSTRIAL_FAMILIES t2, 
> >>>> PLI.PLI_CATALOG_PRODUCTS t1, PLI.PLI_CATALOG_PRODUCTS t0 WHERE 
> >>>> (((t1.ID = ?) AND (t1.PRODUCT_TYPE = ?)) AND ((((t3.lamp_id (+) = 
> >>>> t1.ID) AND (t0.ID (+) = t3.gear_id)) AND (t0.PRODUCT_TYPE = ?)) AND 
> >>>> (t2.ID = t1.family_id)))
> >>>>    bind => [75159, Lamp, Gear]
> >>>>
> >>>> A Product has a @JoinFetch to an IndustrialFamily
> >>>>
> >>>> When I remove the "left join fetch l.gears" from the named query, a 
> >>>> Lamp with its Family is returned
> >>>>
> >>>> Database: Oracle 10G XE
> >>>> jdbc brand version: 10.2.0.4/ojdbc14.jar
> >>>>
> >>>> Leon
> >>>>
> >>>> Tom Ware wrote:
> >>>>> Hi Leon,
> >>>>>
> >>>>>   Can you post the generated SQL?
> >>>>>
> >>>>>   Also, can you post your database and jdbc driver brand and version?
> >>>>>
> >>>>> Thanks,
> >>>>> Tom
> >>>>>
> >>>>> Leon Derks wrote:
> >>>>>> Hi Tom,
> >>>>>>
> >>>>>> When I run the SQL against my database it also doesn't return 
> >>>>>> something. So that is correct.
> >>>>>>
> >>>>>> I think I have to change my named query, but don't know how.
> >>>>>>
> >>>>>> I want to load a Lamp object with its collection of gears. If it 
> >>>>>> has no gears, then the collection has to be empty.
> >>>>>> The query I run now, return no Lamp at all.
> >>>>>>
> >>>>>> Leon
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> Tom Ware wrote:
> >>>>>>> Hi Leon,
> >>>>>>>
> >>>>>>>   What SQL is your query producing?  If you run the SQL against 
> >>>>>>> your database, does it return a result?
> >>>>>>>
> >>>>>>>   To see the SQL, you can increase the logging level.  I suggest 
> >>>>>>> using the maximum logging level when debugging.  To do that, 
> >>>>>>> specify the persistence unit property in your persistence.xml
> >>>>>>>
> >>>>>>> <property name="eclipselink.logging.level" value="FINEST"/>
> >>>>>>>
> >>>>>>> -Tom
> >>>>>>>
> >>>>>>> Leon Derks wrote:
> >>>>>>>> Hello
> >>>>>>>>
> >>>>>>>> Thanks for the answer on my previous question. That works well!
> >>>>>>>>
> >>>>>>>> But now I have another problem.
> >>>>>>>> I want to load an object with a collection that may be empty.
> >>>>>>>>
> >>>>>>>> For example my Lamp object has a @ManyToMany relation with Gear.
> >>>>>>>>
> >>>>>>>> public class Lamp extends Product {
> >>>>>>>>
> >>>>>>>>    @ManyToMany
> >>>>>>>>    @JoinTable(name="PLI_LAMP_GEAR", joinColumns = 
> >>>>>>>> @JoinColumn(name="lamp_id", referencedColumnName = "ID"), 
> >>>>>>>> inverseJoinColumns = @JoinColumn(name="gear_id", 
> >>>>>>>> referencedColumnName = "ID"))
> >>>>>>>>    private List<Gear> gears = new ArrayList<Gear>()
> >>>>>>>>
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> public class Gear extends Product {
> >>>>>>>> }
> >>>>>>>>
> >>>>>>>> In my situation, the Lamp has no Gears, so the join table is 
> >>>>>>>> empty for this lamp.
> >>>>>>>>
> >>>>>>>> But when I try to load the Lamp it returns nothing. I want it 
> >>>>>>>> to return a Lamp (with name, description etc) and an empty 
> >>>>>>>> collection of Gears.
> >>>>>>>>
> >>>>>>>> This is my named query: "select l from Lamp l left join fetch 
> >>>>>>>> l.gears where l.id = :lampId"
> >>>>>>>>
> >>>>>>>> I tried several queries, but always get the message: 
> >>>>>>>> "javax.persistence.NoResultException: getSingleResult() did not 
> >>>>>>>> retrieve any entities."
> >>>>>>>>
> >>>>>>>> Am I doing something wrong?
> >>>>>>>>
> >>>>>>>> greetings,
> >>>>>>>> Leon
> >>>>>>>>
> >>>>>>>> _______________________________________________
> >>>>>>>> eclipselink-users mailing list
> >>>>>>>> eclipselink-users@xxxxxxxxxxx
> >>>>>>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
> >>>>>>> _______________________________________________
> >>>>>>> eclipselink-users mailing list
> >>>>>>> eclipselink-users@xxxxxxxxxxx
> >>>>>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
> >>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>> _______________________________________________
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> >>>>>
> >>>>>
> >>>>
> >>>> _______________________________________________
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> >>>
> >>>
> >>
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> >
> >
> 
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