[hibernate-issues] [Hibernate-JIRA] Updated: (HHH-1395) Hierarchical entity data management using 'modified preorder tree traversal algorithm' (nested set trees)
Christian Bauer (JIRA)
noreply at atlassian.com
Mon Aug 13 06:45:13 EDT 2007
[ http://opensource.atlassian.com/projects/hibernate/browse/HHH-1395?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Christian Bauer updated HHH-1395:
---------------------------------
Summary: Hierarchical entity data management using 'modified preorder tree traversal algorithm' (nested set trees) (was: Recursive - Directed Acyclic graph (tree/parent-child ) entity management using 'modified preorder tree traversal algorithm')
> Hierarchical entity data management using 'modified preorder tree traversal algorithm' (nested set trees)
> ----------------------------------------------------------------------------------------------------------
>
> Key: HHH-1395
> URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1395
> Project: Hibernate3
> Issue Type: New Feature
> Components: core, query-hql
> Environment: Hibernate 3.1 plus Annotations extending EJB3 implementation
> Reporter: James Salt
> Attachments: nestedset.tar.gz
>
> Original Estimate: 3 weeks
> Remaining Estimate: 3 weeks
>
> An enhancement to allow entities to exist in a managed tree (DAG) structure, via the use of property annotations and entity annotations. With an extension to the HQL language to mimic the Oracle recusive query clause.
> This would be classically be useful for Bill of Material uses, or any tree like entity structure.
> I have implemented a homebrew approach using the 'adjacency list method' , and a post persist call back method to set the node path. Although I think a more full blown optimised algorithm would be the 'modified preorder tree traversal algorithm'.
> In the annotations world this could be implemented using an annotation like @Hierarchical to the entity, with a @Parent (mask for @ManyToOne) annotation on the parent field/parameter and @Children (mask for @OneToMany) annotation on the list of children entities.
> Then a postupdate method could be implemented for the entity type, that recalculates the tree meta data -i.e. parent, left and right.
> I believe this would be a valuable extension (useful for many common data models) to the hibernate core product that could be exposed through annotations as I have discussed and the hbm.xml.
> The users of such a system would be aware of the performance implications on insert/update/delete, but gain a massive performance gain on querying a tree data model.
>
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira
More information about the hibernate-issues
mailing list