Re: [eclipselink-users] Caching and @Id

[James Sutherland <jamesssss@xxxxxxxxx>]

Identity will always be maintain within the EntityManager, the cache settings
are just for the shared cache.

You could set the query to be read-only (query hint
"eclipselink.read-only"="true"), or disable the cache for the query  (query
hint "eclipselink.maintain-cache"="false").

Otherwise, you could make every field in the object part of its Id if it
truely has no unique fields.


Zarar Siddiqi wrote:
> 
> Hi,
> 
> I'm have a native query whose results I stuff into an Entity.  The
> query uses a LEFT JOIN and it's awfully hard figuring out uniqueness
> per row since the LEFT JOIN can return null columns.
> 
> I've mapped the results to an @Entity which has one arbitrary column
> defined as an @Id (only because I have to).  Since I have caching
> turned off completely:
> 
>             <property name="eclipselink.cache.type.default" value="NONE"/>
> 
> I expect every entity mapped to be its own object.  However, if the
> result set has three rows with the same value in the @Id field/column,
> the same Java object ends up being there three times instead of three
> different objects.  I realize why it's doing this (looking at the @Id
> and saying "oh well, I already have this object so why map a new one")
> but want to change this behavior.
> 
> I even tried messing with the cache size and shared cache properties
> but no luck.
> 
> Any help would be appreciated.
> 
> Zarar
> 
> 


-----
http://wiki.eclipse.org/User:James.sutherland.oracle.com James Sutherland 
http://www.eclipse.org/eclipselink/
 EclipseLink ,  http://www.oracle.com/technology/products/ias/toplink/
TopLink 
Wiki:  http://wiki.eclipse.org/EclipseLink EclipseLink , 
http://wiki.oracle.com/page/TopLink TopLink 
Forums:  http://forums.oracle.com/forums/forum.jspa?forumID=48 TopLink , 
http://www.nabble.com/EclipseLink-f26430.html EclipseLink 
Book:  http://en.wikibooks.org/wiki/Java_Persistence Java Persistence 
-- 
View this message in context: http://old.nabble.com/Caching-and-%40Id-tp26784831p26800429.html
Sent from the EclipseLink - Users mailing list archive at Nabble.com.