Re: [eclipselink-users] Binding both foreign object reference and foreig

[James Sutherland <jamesssss@xxxxxxxxx>]

Yes, you can just use an @Column, but you will need to make it read-only by
setting insertable=false, updateable=false.  It is up to your application to
keep the two in synch, i.e. in your setCustomer() method you may want to
also set the customerId.



Cody McCain wrote:
> 
> Would someone mind instructing me on how I might go about binding both a
> foreign object reference and a foreign key to an object using
> EclipseLink's JPA implementation?
> 
> For example, I have the following simple domain objects (most methods and
> attributes left out to simplify example):
> 
> @Entity
> @Table(name = "CUSTOMERS")
> public class Customer {
>         @Id
>         @GeneratedValue(strategy = GenerationType.IDENTITY)
>         private long id;
> 
>         @Column(name = "NAME")
>         private String name;
> 
>         // getters and setters below
> }
> 
> @Entity
> @Table(name = "JOBS")
> Public class Job {
>         @Id
>         @GeneratedValue(strategy = GenerationType.IDENTITY)
>         private long id;
> 
>         @Column(name = "DESCRIPTION")
>         private String description;
> 
>         @ManyToOne(fetch = FetchType.LAZY)
>         @JoinColumn(name = "CUSTOMER_ID")
>         private Customer customer;
> 
> 
>         // ? JPA attribute, should I use @COLUMN?
>         private long customerId;
> 
>         // getters and setters below
> }
> 
> 
> I would like to be able to fetch a Job domain object without loading the
> referenced Customer object (this the lazy load strategy).  However, I
> would like to have access to the customerId associated in the link (even
> if it is read-only).  Would I simply add another attribute and map it to
> the foreign key field storing the customerId?  What happens if both this
> field and the reference is changed independently and the Job object is
> persisted (I realize I should write defensive code to prevent this, but
> what is the best pattern)?
> 
> Thanks for the help!
> 
> Regards,
> 
> Cody McCain
> Director of Software Development
> Frac Tech Services, Ltd.
> (817) 349-4330 (office)
> (580) 504-0797 (mobile)
> 
> Ops Support: opssupport@xxxxxxxxxxxx, (817) 764-0432
> 
> 
> 
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-----
http://wiki.eclipse.org/User:James.sutherland.oracle.com James Sutherland 
http://www.eclipse.org/eclipselink/
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