I'm not sure that I understand it correctly. If you don't want to map a field to
a column in a database, you do mark it as @Transient. But do you plan to
override it in orm.xml later on? If not, what's the purpose of such field?
thanks,
-marina
Kem Elbrader wrote:
> I understand that @Transient "means" don't populate and don't write
> but I need a way to keep JPA from populating the field since it
> doesn't even exist in the database that JPA is using.
> Would updateable=false do this? Is there another way to mark a field
> as not being used by JPA that doesn't "mean" that it won't be
> persisted somewhere?
>
> On 7/31/07, Marina Vatkina <Marina.Vatkina_at_sun.com> wrote:
>
>>Kem,
>>
>>You should be able to mark the existing fields as 'updateable=false' but
>>@Transient means not only to skip during write to the database, but also never
>>populate during the read.
>>
>>Regards,
>>-marina
>>
>>Kem Elbrader wrote:
>>
>>>Here's the situation.
>>>
>>>A company uses a database that stores information about its customers.
>>>A web interface is available for customer service representatives to
>>>update the customers name, phone number, etc. The web interface is not
>>>suitable for customers to use so the company has a calling center that
>>>enables the customers to request changes. The database and web
>>>interface were produced by a third party which is unwilling to make
>>>changes to the existing system. The third party does provide a web
>>>service with operations to create, update, and delete the data.
>>>
>>>The company wants to provide a web interface to allow customers to
>>>update their information themselves. Further, the company wants to
>>>produce additional services which will require extra data that is not
>>>stored in the original database. For example, some of the entities
>>>represented in the original database simply need some properties added
>>>to them. It's not viable to reproduce the existing system. So a new
>>>system must be created that is capable of updating the data in the
>>>existing system, persist the new data and provide the new
>>>functionality.
>>>
>>>I was hoping I could use JPA to model the new and old data together so
>>>that a single object could be used in the cases where simple
>>>properties need to be added to the existing entities. Is this
>>>reasonable?
>>>
>>>Here is my current approach.
>>>
>>>@Entity
>>>@EntityListeners({UserListener.class})
>>>class ExampleUser {
>>> @Id String login; // new data
>>> @Transient String name; // existing data
>>>
>>> String getLogin() { return login; }
>>> void setLogin(String login) { this.login= login; }
>>>
>>> String getName() { return name; }
>>> void setName(String name) { this.name = name; }
>>>}
>>>
>>>class UserListener {
>>> @PostLoad void initializeUser(Object entity) {
>>> // use web service to obtain the users name
>>> // copy the name to ExampleUser.name
>>> }
>>> @PostPersist void saveUser(Object entity) {
>>> // use web service to save ExampleUser.name
>>> }
>>>}
>>>
>>>I believe this is similar to your suggestion but I'm not quite sure
>>>what you meant. Can you clarify your suggestion?
>>>
>>>On 7/30/07, Craig L Russell <Craig.Russell_at_sun.com> wrote:
>>>
>>>
>>>>Hi Kem,
>>>>
>>>>Can you model this as an EJB that is created by other EJBs and that
>>>>contacts the third party web service plus the Entity?
>>>>
>>>>Craig
>>>>
>>>>On Jul 30, 2007, at 11:47 AM, Kem Elbrader wrote:
>>>>
>>>>
>>>>
>>>>>I have an entity which has a few properties that aren't persisted to
>>>>>the database but rather obtained from a third party web service. How
>>>>>would you suggest going about accomplishing this?
>>>>>
>>>>>On 7/30/07, Craig L Russell <Craig.Russell_at_sun.com> wrote:
>>>>>
>>>>>
>>>>>>Hi Kem,
>>>>>>
>>>>>>I'd suggest you rework your design such that you only use references
>>>>>>"from" EJBs "to" Entities and other EJBs.
>>>>>>
>>>>>>Having Entities reference EJBs violates the basic POJO model.
>>>>>>
>>>>>>Regards,
>>>>>>
>>>>>>Craig
>>>>>>
>>>>>>On Jul 30, 2007, at 11:22 AM, Kem Elbrader wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>Is it possible to inject an EJB into an Entity? If not is there
>>>>>>>another way to get a reference to a EJB from an Entity?
>>>>>>>
>>>>>>>Example:
>>>>>>>
>>>>>>>@Entity
>>>>>>>public class Customer {
>>>>>>>
>>>>>>> @EJB
>>>>>>> CustomerAction customerAction;
>>>>>>>
>>>>>>> @PostLoad
>>>>>>> void initialize() {
>>>>>>> // do stuff with customerAction...
>>>>>>> }
>>>>>>>}
>>>>>>
>>>>>>Craig Russell
>>>>>>Architect, Sun Java Enterprise System http://java.sun.com/products/
>>>>>>jdo
>>>>>>408 276-5638 mailto:Craig.Russell_at_sun.com
>>>>>>P.S. A good JDO? O, Gasp!
>>>>>>
>>>>>>
>>>>>>
>>>>
>>>>Craig Russell
>>>>Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
>>>>408 276-5638 mailto:Craig.Russell_at_sun.com
>>>>P.S. A good JDO? O, Gasp!
>>>>
>>>>
>>>>
>>