Re: [eclipselink-users] loading collection problem

[Tom Ware <tom.ware@xxxxxxxxxx>]

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
>
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