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Re: [eclipselink-users] Discriminator and Inheritance.strategy
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Hello Guy,
unfortunately we have the Inheritance.JOIN strategy.
I don't understand why there's a discriminator needed for this strategy because which class an
object is instance of is determined by the entry in the "sub"-table, isn't it?
kind regards,
Michael
Guy Pelletier schrieb:
> A discriminator column is not needed for a TABLE_PER_CLASS strategy.
>
> The discriminator column is used to determine which class of object that
> row represents.
>
> Cheers,
> Guy
>
> ----- Original Message ----- From: "Michael Simons"
> <michael.simons@xxxxxxxxxxx>
> To: <eclipselink-users@xxxxxxxxxxx>
> Sent: Friday, November 27, 2009 6:33 AM
> Subject: [eclipselink-users] Discriminator and Inheritance.strategy
>
>
>> Hello,
>>
>> I'm trying to port a client/server application first to JPA to enable
>> the 3-tier migration.
>> At the moment I try to use EclipseLink as JPA implementation.
>> The first exception I fall over said "Unknown column 't2.DTYPE' in
>> 'field list'"
>>
>> Seems like EclipseLink always needs a discriminator column even if the
>> inheritance strategy is
>> JOIN or TABLE_PER_CLASS.
>> Is this correct?
>> And if so, what is it good/needed for?
>>
>> [EclipseLink 1.2.0, database=MySQL 5]
>>
>> Kind Regards,
>> Michael
>> _______________________________________________
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>> eclipselink-users@xxxxxxxxxxx
>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
>>
>
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