[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-1742) SQL join is missed in Criteria queries for join/alias on foreign key as part of composite primary key (many-to-one association)

[Mattias Jiderhamn (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-1742?page=comments#action_25517 ] 

Mattias Jiderhamn commented on HHH-1742:
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After a bit of debugging it seems the problem lies within the JoinWalker (or specifically CriteriaJoinWalker). When creating a list of associations that may be used for joins (in walkEntityTree()) it only looks at the properties of the persister/OuterJoinLoadable (SingleTableEntityPersister in my case). The composite-id/key-many-to-one mappings are not listed as properties, and therefore not even considered for joins. So, when AbstractEntityJoinWalker creates the actual statement, it doesn't know about the relation to the "parent" (key-many-to-one).

Not sure yet what the correct change would be, but hopefully somebody could use the information above or I find the time to try something out.

> SQL join is missed in Criteria queries for join/alias on foreign key as part of composite primary key (many-to-one association)
> -------------------------------------------------------------------------------------------------------------------------------
>
>          Key: HHH-1742
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1742
>      Project: Hibernate3
>         Type: Bug

>   Components: query-criteria
>     Versions: 3.2.0 cr1
>  Environment: Windows XP, Oracle 10g, HSQLDB
>     Reporter: Viatcheslav Sysoltsev (Slavka)
>  Attachments: HibernateTest.zip
>
>
> I've stuck with Criteria API on issue, that the join is sometimes missed from generated SQL query doing joining on foreign key.
> Here is the little example I've made to demonstrate the problem (also attached as standalone runnable eclipse project)
> There are two tables:
> FAMILY
> familyName as primary key
> familyProperty
> PERSON
> familyName as foreign key on FAMILY   } the both fields make primary key 
> personName                                               } of PERSON
> Doing query on person like
> session.createCriteria(Person.class)
>      .createCriteria("id.family")
>      .add(Restrictions.eq("familyProperty", "whatever"))
>      .list();
> Causes query 
> Hibernate: select this_.FAMILY_NAME as FAMILY1_1_0_, this_.PERSON_NAME as PERSON2_1_0_ from PERSON this_ where family1_.FAMILY_PROPERTY=?
> .. which is rather invalid
> The same by the way happens doing query 
> session.createCriteria(Person.class)
>      .createCriteria("id.family")
>      .add(Restrictions.eq("familyName", "whatever"))
>      .list();
> The query 
> select this_.FAMILY_NAME as FAMILY1_1_0_, this_.PERSON_NAME as PERSON2_1_0_ from PERSON this_ where family1_.FAMILY_NAME=?
> .. is invalid either though it can be made valid without join, because family1_.FAMILY_NAME can be accessed through this_.FAMILY_NAME
> The attachment is a whole eclipse project, pretty straightforward, with hsqldb, which demonstrates the SQL generated and the problem.
> I suspect this bug may be caused by the fix to HH-528 (component.manyToOne.id in HQL causes join).
> The priority should be high because
> session.createCriteria(Person.class)
> 	.createAlias("id.family", "family")
> 	.add(Restrictions.eq("family.familyProperty", "whatever"))
> 	.list();
> doesn't work either. 
> In effect there is no way to cause join on foreign key with Criteria API. Whatever in hibernate blocks join on foreign key rather zealous.

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