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Conditional LEFT JOIN criteria API [message #696301]

Wed, 13 July 2011 16:40

Messages: 13
Registered: June 2011

Junior Member

Hello,

I'm trying to do a Conditional LEFT JOIN with criteria API..but it doesn't work as expected.

Join ed = from.join("somethingCollection", JoinType.LEFT);

Path path = ed.get("some").get("hasEL");
Predicate p = cb.equal(path, Boolean.TRUE);
predicateList.add(p);

this adds a where clause t1.hasEL = true and I need it to be added to the ON expression.

Is it possible?

more details on this issues: http://forums.oracle.com/forums/thread.jspa?threadID=2177735 think is similar to mine

regards,
la00

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Re: Conditional LEFT JOIN criteria API [message #698557 is a reply to message #696301]

Tue, 19 July 2011 17:25

James Sutherland

Messages: 1939
Registered: July 2009
Location: Ottawa, Canada

Senior Member

Only the relationship join is put in the ON clause in Criteria or JPQL, there is no way to affect the ON clause.

Why do you need the comparison in the ON clause? Use a left join for the path as well to ensure it is outer joined, what is the full query?
Try to re-word it to not require the ON clause.

It is possible in EclipseLink to define a OneToOneQuery key that allows a custom ON clause.

See/vote for bug,
https://bugs.eclipse.org/bugs/show_bug.cgi?id=312146

James : Wiki : Book : Blog : Twitter

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