[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-3646) implement Criteria API querying of collection-of-component

[Sergey Pulyaev (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-3646?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=34531#action_34531 ] 

Sergey Pulyaev commented on HHH-3646:
-------------------------------------

There is a problem if we have Many-To-Many collection.
In this situation function CriterionJoinWalker.generateTableAlias is called twice - for reference table and then - for destination table,
so there will be two aliases with the same name in query - and it will crush with error:

Caused by: java.sql.SQLException: The correlation name '111' is specified multiple times in a FROM clause.

Sample SQL generated:

    select
        this_.id as y0_,
        sr1_.id as y1_ 
    from
        roles this_ 
    inner join
        role_inheritors sr1_ 
            on (
                this_.id=sr1_.role_id
            ) 
    inner join
        roles sr1_ 
            on (
                sr1_.inherit_id=sr1_.id
            ) 
    where
        this_.id<>sr1_.id

> implement Criteria API querying of collection-of-component
> ----------------------------------------------------------
>
>                 Key: HHH-3646
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3646
>             Project: Hibernate Core
>          Issue Type: Patch
>          Components: query-criteria
>    Affects Versions: 3.2.6
>         Environment: hibernate 3.2.6, tested on linux 64-bit openjdk 1.6 (jdk1.5 for compiling).  mapping created under annotations 3.3.1ga
>            Reporter: David Mansfield
>         Attachments: hib-core-query-collection-of-elements-3_2_6-ver2.patch, hib-core-query-collection-of-elements-3_2_6.patch
>
>   Original Estimate: 1 day
>  Remaining Estimate: 1 day
>
> the attached patch implements a first cut, extremely rough, yet working extension of the CriteriaQueryTranslator class to allow for querying of properties of components inside a collection, or querying properties of associated elements of components inside a collection.  eg for
> * code is lightly tested, this example is for illustrative purposes only
> * i use annotations, so my example is expressed in those terms, and i've only tested with mappings generated via annotations, however, the modifications only apply to the core.
> @Entity
> class Order {
>    @Id
>   String id;
>   @CollectionOfElements
>   Set<OrderLineItem> lineItems;
> }
> @Embeddable
> class OrderLineItem {
>   @ManyToOne
>   Product product;
>   Integer quantity;
> }
> @Entity
> class Product {
>   String name;
> }
> Then we can now do:
> Criteria c = session.createCriteria(Order.class)
>    .createCriteria("lineItems")
>    .add(Restrictions.gt("quantity", new Integer(1))
>    .list();
> or
> Criteria c = session.createCriteria(Order.class)
>    .createCriteria("lineItems")
>    .createCriteria("product")
>    .add(Restrictions.like("name", "cake%")
>    .list();

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