@JoinFetch does nothing (EclipseLink)

Question

I have a Base entity with a many-to-one relationship with a Nested object. I want to order a request at Nested.name, where the name can be null. Even if the name is null, I want the query to return this string. So I'm trying to get EclipseLink to generate queries that have LEFT JOINs together, instead of selecting from both tables.

I annotated the relationship between the base and the nested with the @JoinFetch annotation as follows:

@ManyToOne(fetch = FetchType.EAGER) @JoinColumn(name = "BASE_ID") @JoinFetch(value = JoinFetchType.OUTER) private Nested nested; 

However, this does not seem to have any effect on requests created by EclipseLink. Actual generated request

 SELECT ... FROM BASE t0, NESTED t1 WHERE (t1.ID = t0.BASE_ID) ORDER BY t1.NAME ASC... 

while I expect something along the lines

 SELECT ... FROM BASE t0 LEFT JOIN NESTED t1 ON (t1.ID = t0.BASE_ID) ORDER BY t1.NAME ASC... 

I use the JPA 2.0 criteria API to create and execute queries. Even if I explicitly create a join query using the criteria API, the resulting query will look like the first, without joins. Explicit joining when building a query seems to work fine with Hibernate, but does not affect the resulting query in EclipseLink.

I probably have something missing, so any advice is welcome.

thanks

Answer 1

I think the problem is in your orderBy (which does not use an external join, therefore invalidates the fetch outer join).

How do you set up the order? Do you use an external connection for this?