[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-16) Explicit joins on unrelated classes

[hugo (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-16?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=35402#action_35402 ] 

hugo commented on HHH-16:
-------------------------

The main need here is to be able to add criteria on the clause of an *outer* join ! Because in those cases the semantic of a criteria in the ON clause or in the WHERE clause is completely different.

Today it's not possible to do that, and thus some kind of queries can not be expressed in HQL.

I'm not sure the current issue will address that, but it appears HB-1441 clearly is the heart of the problem.

> Explicit joins on unrelated classes
> -----------------------------------
>
>                 Key: HHH-16
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-16
>             Project: Hibernate Core
>          Issue Type: New Feature
>          Components: core
>    Affects Versions: antlr-rework
>         Environment: Any
>            Reporter: David Lloyd
>            Assignee: Steve Ebersole
>             Fix For: antlr-rework
>
>
> It would be nice to be able to do explicit joins on unrelated classes with HQL:
> (hope this renders correctly)
>           select empl, phone
>             from org.example.Employee empl
>  left outer join org.example.PhoneBook phone
>               on phone.lastName = empl.lastName
>              and phone.firstName = empl.firstName
>            where empl.salaryGrade > 10
> Note that this would also implicity solve HB-1089 because you could list join criteria that match what Hibernate would have chosen anyway (i.e., list a many-to-one relationship as a criteria explicitly).
> Syntactically this could be disambiguated from the existing join syntax because the token after "join" is a class name rather than a property name.

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