[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-6593) Fetch joining subelements of a one-to-one or many-to-one association

[Christian Beikov (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-6593?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=45113#comment-45113 ] 

Christian Beikov commented on HHH-6593:
---------------------------------------

The problem with the workaround is, that a select distinct will not work anymore, because join fetching sub collections without the alias will end up in the following Exception:


org.hibernate.QueryException: query specified join fetching, but the owner of the fetched association was not present in the select list [FromElement{explicit,collection join,fetch join,fetch non-lazy properties,classAlias=null,role=package.MyClass.mapField,tableName={none},tableAlias=map_field1_,origin=null,columns={,className=null}}] [SELECT DISTINCT ...]
	at org.hibernate.hql.ast.tree.SelectClause.initializeExplicitSelectClause(Unknown Source)
	at org.hibernate.hql.ast.HqlSqlWalker.useSelectClause(Unknown Source)
	at org.hibernate.hql.ast.HqlSqlWalker.processQuery(Unknown Source)
	at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(Unknown Source)
	at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(Unknown Source)
	at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(Unknown Source)
	at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(Unknown Source)
	at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(Unknown Source)
	at org.hibernate.hql.ast.QueryTranslatorImpl.compile(Unknown Source)
	at org.hibernate.engine.query.HQLQueryPlan.<init>(Unknown Source)
	at org.hibernate.engine.query.HQLQueryPlan.<init>(Unknown Source)
	at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(Unknown Source)
	at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(Unknown Source)
	at org.hibernate.impl.AbstractSessionImpl.createQuery(Unknown Source)
	at org.hibernate.impl.SessionImpl.createQuery(Unknown Source)

This has to work, it is essential for writing HQL queries. I can not imagine that no one had this problem before! Please take care of that bug asap!

> Fetch joining subelements of a one-to-one or many-to-one association
> --------------------------------------------------------------------
>
>                 Key: HHH-6593
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-6593
>             Project: Hibernate ORM
>          Issue Type: Bug
>    Affects Versions: 3.6.6
>            Reporter: Christian Beikov
>            Priority: Critical
>              Labels: HQL, fetch, hibernate, join
>
> The problem is discussed on the forum a long time ago. I just found the topic and i wanted to report that this bug is still available in 3.6.6
> https://forum.hibernate.org/viewtopic.php?f=1&t=987905&start=0
> Here a concrete example from my usecase:
> class A{
>  private B b;
> }
> class B{
>  private Map<String, C> map;
> }
> class C{
>  private String c;
> }
> Just imagine that the classes and fields would be annotated right ;)
> Now the problem in my case was that i wanted a list of A elements with fetch joined B and of course it's map.
> I tried the following query:
> FROM A a LEFT OUTER JOIN FETCH a.b bElem LEFT OUTER JOIN bElem.map cMap
> and i got a NullPointerException just like the users which posted in the given topic.
> My workaround was:
> FROM A a LEFT OUTER JOIN FETCH a.b bElem LEFT OUTER JOIN a.b.map cMap
> The main problem now is, that i have a dynamic fetch profile system which won't work correctly if this issue is not solved.

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