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From Majeed Arni <ma...@sbcglobal.net>
Subject Re: Bug when persisting two related objects
Date Fri, 11 May 2007 14:03:27 GMT

The DDL is handmade. There is nothing in code about Identity. It is done in
Database. 

I found a workaround for this problem by just moving the code around. Looks
like a bug is the wrong message it sends.

Also, is there a way to generate DDL from Java code? I saw "create=true" for
Derby, does that work for DB2 also? Thanks again.

Majeed



Kevin Sutter wrote:
> 
> I don't think it matters whether you are using DB2 or any other database.
> Getting back to one of Patrick's earlier requests...  Can you post more
> information on the Project and Base classes?  You've posted a snippet of
> the
> Base class and it's ID, but how are you defining the Project and it's ID?
> As Abe as pointed out, if two classes in an inheritance hierarchy use the
> same ID class, then unique id values need to be provided for each
> instance.
> Could you also post your DDL for generating your tables?  Was this
> hand-generated DDL or created by the OpenJPA tooling?  Thanks.
> 
> Kevin
> 
> On 5/10/07, Majeed Arni <marni@sbcglobal.net> wrote:
>>
>>
>> I am using DB2 to generate the Identity as in the DDL:
>> ID BIGINT NOT NULL GENERATED BY DEFAULT AS IDENTITY (START WITH 1,
>> INCREMENT
>> BY 1)
>>
>> And in code for the base class:
>> @MappedSuperclass
>> @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
>> public abstract class Base {
>> .....
>>         @Id
>>         @GeneratedValue(strategy = GenerationType.IDENTITY)
>>         @Column(name = "ID")
>>         private long someID;
>>
>> .....}
>>
>> Will this not use a unique ID generator per derived class? Is there a
>> better
>> way of doing it in DB2? Thanks for the help.
>>
>> Majeed Arni
>>
>>
>>
>> Abe White wrote:
>> >
>> > Are the two types related by inheritance?  If two classes in an
>> > inheritance hierarchy use the same id class, then every instance of
>> > both classes must have a distinct id value.  If you want instances in
>> > inheritance-related classes to be able to have the same id values,
>> > then you must use different id classes for different classes in the
>> > inheritance hierarchy.
>> >
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>> --
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>>
>>
> 
> 

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