Re: [eclipselink-users] How to save a specific instance of an Entity

[Tom Ware <tom.ware@xxxxxxxxxx>]

By definition an Entity has an identity. (i.e. one instance of an Entity can 
exist with a @Id)  As a result any reference to an entity will have to join tables.

It sounds more like you want your service definition to be an Embeddable.  If it 
were an Embeddable, the Entity that contained it would own it and you would not 
need a reference.

-Tom

RogerV wrote:
> Hi
>
> I've got two entities. @Entity ServiceDefinition which comprises parameters
> that control the flow of a program to perform a service. Because the
> execution of the service can fail, I have my second entity 
>
> @Entity 
> public class ServiceTransaction {
>
> private ServiceDefinition serviceDefinition;
>
> .. getters/setters
> }
>
> What I want to store in ServiceTransaction is not a pointer to the
> definition held in @Entity ServiceDefinition but the specific instance of
> ServiceDefinition that I'm using (because ServiceDefinition could change).
> In addition I would like to store the instance as an object rather than as a
> collection of data elements so that I can restore its state. At runtime
> Eclipselink is complaining that I don't have join details defined between
> ServiceTransaction and ServiceDefinition.
>
> Is it possible to do what I want, and if so, how?
>
> Regards