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Outer Join with 3 tables is not working [message #844402]

Fri, 13 April 2012 20:53

Eclipse User

Table A has One to One relation with Table B on non primary key of Table A
Table A has One to One relation with Table C on primary key of Table C

While I retrieve rows of Table A with simple JPQL query, I am getting outer join effect but, Eclipse link is issuing One select for rows of Table A and One select to fetch related objects of Table B and Table C. So if Table A has 25 rows, I am seeing 51 selects in all.

How can I tell Eclipselink to issue one select with 2 outer joins.

Thanks
Suri

Re: Outer Join with 3 tables is not working [message #846672 is a reply to message #844402]

Mon, 16 April 2012 11:29

Eclipse User

You can use "left join fetch" in your query.
Or use batch fetching through hints.

See,
http://java-persistence-performance.blogspot.com/2010/08/batch-fetching-optimizing-object-graph.html

Re: Outer Join with 3 tables is not working [message #850787 is a reply to message #846672]

Fri, 20 April 2012 06:28

Eclipse User

Thank you James, that was a very good article of yours.

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