[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-3414) fetch profiles
Steve Ebersole (JIRA)
noreply at atlassian.com
Wed Aug 20 12:46:44 EDT 2008
[ http://opensource.atlassian.com/projects/hibernate/browse/HHH-3414?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_30949 ]
Steve Ebersole commented on HHH-3414:
-------------------------------------
Types of fetches:
1) join - an outer join fetch
2) select - a subsequent select fetch (n+1)
3) subselect - support for this requires significant refactoring to the subselect loading code, and as such it is not planned for the initial feature release.
> fetch profiles
> --------------
>
> Key: HHH-3414
> URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3414
> Project: Hibernate3
> Issue Type: New Feature
> Components: core, metamodel
> Reporter: Steve Ebersole
> Assignee: Steve Ebersole
> Fix For: 3.4
>
>
> The concept of fetch profiles as we are discussing here is basically to allow users to dynamically affect the mapped fetching strategy for associations at runtime.
> Consider the following example:
> <class name="Person">
> ...
> <set name="addresses" lazy="true" fetch="subselect" ...>
> ...
> </set>
> </class>
> <class name="Address">
> ...
> </class>
> This follows the normal recommendation to map associations as lazy and use a dynamic fetching strategy (ala HQL/Criteria) to modify this lazy behavior at runtime.
> The fetaure discussed here would allow the same behavior for loading as well:
> <hibernate-mapping>
> <fetch-profile name="person-details">
> <fetch path="Person.addresses" style="join"/>
> </fetch-profile>
> </hibernate-mapping>
> Or:
> <hibernate-mapping>
> <class name="Person">
> ...
> <fetch-profile name="person-details">
> <fetch path="addresses" style="join"/>
> </fetch-profile>
> <set name="addresses" lazy="true" fetch="subselect" ...>
> ...
> </set>
> </class>
> </hibernate-mapping>
> Now, doing:
> session.enableFetchProfile( "person-details" ).get( Person.class, 1 )...
> will load Person#1 as well as their addresses in a single joined query.
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