The business of mapping a Map is very confusing.

The docs and FAQ (http://www.hibernate.org/329.html#A12) state that Map isn't fully supported, but "Hibernate Annotations does support Hibernate style Map mapping (ie explcit column for the map key) for Map<Element, ...> and Map<Embeddable, ...> (support for Map<Entity, ...> is expected later)".

However, looking at the changelog for my version of hibernate-annotations - 3.2.0.CR1 - there are a number of issues that have been recently been fixed in this area, e.g.

* Support for Map<Entity, Entity> - http://opensource.atlassian.com/project ... se/ANN-327
* http://opensource.atlassian.com/project ... se/ANN-281

The question is, is it now possible to easily persist the Map in this getter:



with annotations? If so, how? Please provide as full as code as possible if you can, I only started learning hibernate yesterday :-)

Oliver

Is it actually possible to map this directly or would you have to do something else like


where



If so, how would you annotate that Map?

Hi Oliver,

according to the forum topic
http://forum.hibernate.org/viewtopic.php?t=956662&highlight=map+entity

As I would call Map<MyClassA, SortedSet<MyClassB>> a "Collection of collections", you will most likely have to realize your SortedSetMyClassB, i.e. encapsulate the set in an entity.

As for the question of the proper annotation for the map, I would suggest just using

In absence of javax.persistence.MapKey, Hibernate will automatically offer real map support. If you need to override the default column for the map-key, you can add something like

Thanks, I've extended Java's SortedSet to make my own SortedSetMyClassB and it seems to work.