Re: [eclipselink-users] Composite foreign primary key in 3 tables

[Horat <crolla@xxxxxxxxxxxxxxxxxxx>]

Hi,

thanks for your help.

I tried your suggestion for the Primary-Key-classes. The previous error does
not occur anymore, but my example does still not work.

After updating to Eclipselink 2.1.0 I get an Excpetion while parsing the
PersistenceUnit:
Internal Exception: java.lang.ClassCastException:
org.eclipse.persistence.internal.jpa.metadata.accessors.mappings.IdAccessor
cannot be cast to
org.eclipse.persistence.internal.jpa.metadata.accessors.mappings.ObjectAccessor

This error persists if I change the IdClass to an Embeddable and embed it in
Class NumericalData.

I have uploaded the actual Entity classes for this example, that correspond
to the scenario described in my first post. Additionally the orm.xml is
attached that contains all mappings.

http://old.nabble.com/file/p29008527/orm.xml orm.xml  Entity-Mappings
http://old.nabble.com/file/p29008527/Device.java Device.java  (Refers to
class A)
http://old.nabble.com/file/p29008527/Channel.java Channel.java  (Refers to
class B)
http://old.nabble.com/file/p29008527/ChannelPK.java ChannelPK.java  (Refers
to class BPK)
http://old.nabble.com/file/p29008527/NumericalData.java NumericalData.java 
(Refers to class C)
http://old.nabble.com/file/p29008527/DataPK.java DataPK.java  (Refers to
class CPK)

It is really frustrating to see Eclipselink not working with these very
simple relations.

Thanks again for help.





christopher delahunt wrote:
> 
> Hello,
> 
> The specification states you should have A's id within the BPK class, 
> not A itself.  The same goes for CPK, it should contain int time and BPK 
> b as attributes.
> Please feel free to file a bug to have the error message improved if 
> changing this resolves the problem.
> 
> Best Regards,
> Chris
> 
> On 24/06/2010 3:15 AM, Horat wrote:
>> Hello, 
>>
>> I have three tables:
>>
>> Table A:
>> id (PK)
>>
>> Table B:
>> aid (FK from A, PK)
>> num (PK)
>>
>> Table C:
>> aid (FK from A, PK)
>> bnum (FK from B, PK)
>> time (PK)
>>
>>
>> With eclipselink i have annotated the ManyToOne-relation from B to A as
>> follows:
>> @Entity
>> public class A {
>>  @Id
>>  public int id;
>> }
>>
>> @IdClass (BPK.class)
>> @Entity
>> public class B {
>>  @Id
>>  @ManyToOne
>>  @JoinColumn (name="aid" referencedColumnName="id")
>>  public A a;
>>
>>  @Id
>>  public int num;
>> }
>>
>> With BPK as the IdClass containing a and num.
>>
>> This does work as intended!
>>
>> For table C I annotated the ManyToOne-relation from C to B as follows:
>>
>> @IdClass (CPK.class)
>> @Entity
>> public class C {
>>  @Id
>>  @ManyToOne
>>  @JoinColumns ({ @JoinColumn (name="aid", referencedColumnName="aid"),
>> @JoinColumn(name="bnum", referencedColumnName="num") })
>>  public B b;
>>
>>  @Id
>>  public int time;
>> }
>>
>> With CPK being the IcClass containing B and time.
>>
>> When I try to run this I get an error:
>> org.eclipse.persistence.exceptions.ValidationException
>> Exception Description: The composite primary key attribute [b] of type
>> [null] on entity class [class C] should be of the same type as defined on
>> its primary key class [CPK]. That is, it should be of type [B].
>>
>> I don't get it why the type of b is null. Obviously it is not.
>>
>> Am I missing out anything?
>>
>> Thanks for replying.
>>   
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> 

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