[Hibernate-issues] [Hibernate-JIRA] Commented: (HB-520) Add Distinct to Criteria API

[Artti J. (JIRA) <no...@at...>]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HB-520?page=comments#action_19631 ] 

Artti Jaakkola commented on HB-520:
-----------------------------------

Problem with setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY) is that it's done only after the query is executed.

If you happen to have criteria.setMaxResults(10) and first 8 items equal with each other, then you get only 3 items as a result:

List results = session
    .createCriteria(User.class)
    .setResultTransformer(CriteriaSpecification.DISTINCT_ROOT_ENTITY)
    .setMaxResults(itemCount.intValue())
    .list();

Now I don't know if I should fetch all the items from database and then just cut the first 10 or what...

> Add Distinct to Criteria API
> ----------------------------
>
>          Key: HB-520
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/HB-520
>      Project: Hibernate2
>         Type: New Feature
>   Components: core
>     Versions: 2.1 rc1
>  Environment: Hibernate 2.1+, (Any DB)
>     Reporter: Stephen Owens
>     Priority: Minor

>
>
> Need the ability to specify that results of a Criteria query should be 'DISTINCT', especially when joining to a collection. So the Criteria equivalent of the HQL statement 
> "select distinct parent from Parent as parent join Parent.children as child where child.age>5"

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