Re: [eclipselink-users] criteriaquery : fetch not working

[Yannick Majoros <yannick.majoros@xxxxxxxxxxxx>]

 Hi,

Thanks a lot, it's much better now :-) You put some light in the dark 
zones in my mind concerning Eclipselink ;-)

I changed some defaults in the mapping (from default to lazy in most cases).

I also added @BatchFetch annotations on some @OneToMany mappings. Some 
things just never need to be read one by one. As I can't go into the 
whole team's code (everyone doing things without too much concertation), 
I think that's the best thing to do.

A few more questions:

- @BatchFetch introduces a nice default, but in some cases, such as the 
one I was describing, I'd like to override that like this:
        root.fetch(EtdOffEtd_.etdOffEtdSesCollection, JoinType.LEFT);

Now, if I do both this and leave the @BatchFecth annotation, it just 
seems to do both. Is there a way to disable the batch fetch when needed?

- what's the difference between root.fetch() and root.join() in this case?
- I don't really understand if the link you provided could help me 
further? Could I still improve the code with this?

Best regards,

Yanncik


Le 4/08/2011 19:20, Tom Ware a écrit :
> The default is LAZY for xToMany and EAGER for xToOne.  To allow LAZY 
> to work on xToOne, you will have to not only ensure the mapping is 
> marked as LAZY, but also ensure EclipseLink can weave the classes.  
> The classes will be weaved by default on a Java EE 5 compliant 
> container.  You will have to use set the eclispelink jar file as with 
> the -javaagent flag in Java SE if you are running standalone. Other 
> cases require other configuration - which are you using?
>
> Looking more closely at your query, you are likely getting more joins 
> than you need.  For instance, you are both fetch joining and joining 
> EtdOffEtd_.etdInscCoursCollection.  Each of those will result in a join.
>
> You may want to consider using our fetch join query hint that allows 
> you to do multiple level fetch joins.
>
> http://wiki.eclipse.org/Using_EclipseLink_JPA_Extensions_%28ELUG%29#Join_Fetch