Re: [eclipselink-users] Updating Join Views

[Andreas Schmidt <Andreas.Schmidt@xxxxxxxxx>]

RogerV wrote:
> 
> 
> 
> Andreas Schmidt wrote:
>> 
>> Hello Roger,
>> 
>> if you use faces, you can put a <t:saveState value="#{Bean or entity}"/>
>> tag in you page.
>> This will restore all fields of the entity (or the entire bean). 
>> If your framework does not support such a tag and the bean is in request
>> mode, then you can update the fields as shown below:
>> 
>> 
>> 	public void save() {
>> 
>> 
>> 		ApplicationBean applicationBean = (ApplicationBean)
>> getBean("applicationBean");
>> 		EntityManager em = applicationBean.getEMF().createEntityManager();
>> 
>> 		try {
>> 			em.getTransaction().begin();
>> 
>> 			Entity e = em.find(Entity.class, this.entity.getId());
>> 
>> 			e.setField1(this.entity.getField1());
>> 			e.setSprache(this.entity.getField2());
>> 
>> 			em.getTransaction().commit();
>> 
>> 			
>> 		} catch (Exception e) {
>> 			this.error(e.toString());
>> 
>> 		} finally {
>> 			em.close();
>> 		}
>> 
>> 	}
>> 
> 
> Hi Andreas
> 
> I've tried your approach which works fine, but has led me to a fresh
> problem. What I'm doing now is reading the data via EclipseLink using the
> view and displaying it to a web page. When the data is posted back I find
> the entity in the base table I want to update and update the fields
> necassary as you describe. Checking in the database shows that the data
> field and the version field (optimistic locking) have been correctly
> updated. However, when I re-load the data from the view I see the
> pre-updated data, EclipseLink is reading from a cache, not the database. 
> 
> I've tried @Cache(disableHits = true) and @Cache(refreshOnlyIfNewer =
> true) on my view.java but neither seem to make any difference. What do I
> need to do to force EclipseLink to reload the view data from the database.
> 
> Regards
> 

Hello Roger,  
as you said, the view will be cached and not updated with the fresh values
from the database.
I read somewhere, that you have to "invalidate" the cache of the view (can'
remeber how this can be achieved).

I my case I use the following annotation in the "view entity", since my
resultset is small and performance is not an issue:

@Cache(expiry = 1000 * 60)
//force cache refresh every minute (View !)

You can increase this values if required or disbale caching for this entity
in your persistance.xml
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