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In JPA fetch join, you can get the entity and its associated entities in one native SQL query. Is there a way to do similar in JDO? I'm using DataNucleus implementation.

Bewang
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JDO has fetch groups, which is way more powerful than any current feature in JPA. Simply read the JDO spec.

Bart
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DataNucleus
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  • Thanks for replying. I don't think fetch groups help in my case. I'm suffering "N queries" issue in ORM, after get a list of objects in one query, I have to send N queries to retrieve the associated objects. I'm wondering if JDO supports "Fetch join" or "Batch fetch" like this article http://java-persistence-performance.blogspot.com/2010/08/batch-fetching-optimizing-object-graph.html. – Bewang Nov 30 '12 at 21:32
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    obviously fetch groups gives you all the control you need (to add any field to the list of what will be fetched), and without definition of query etc its pointless saying more. – DataNucleus Dec 01 '12 at 06:43
  • Because comments have limit on characters, I have my problem posted here: http://ben-tech.blogspot.com/2012/11/bad-performance-of-hive-meta-store-for.html. Could you let me know how JDO fetch groups help solving my problem? – Bewang Dec 02 '12 at 19:06