Hello folks,

I need to find the foreign key (collection key) of a OneToMany relation.

I have the following collection owner mapping:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Database.Core.TimeZone,Database" table="TimeZone">

<id name="TimeZoneId" column="TIME_ZONE_ID" type="Int16" unsaved-value="0">
<generator class="native"/>
</id>
<bag name="AnnotationListCreated" inverse="true" lazy="true" >
<key column="CREATION_TIME_ZONE_ID" />
<one-to-many class="Database.Core.Annotation,Database" />
</bag>
<bag name="AnnotationListModified" inverse="true" lazy="true" >
<key column="MODIFIED_TIME_ZONE_ID" />
<one-to-many class="Database.Core.Annotation,Database" />
</bag>

<property column="TIME_ZONE_NAME" type="String" name="TimeZoneName" not-null="true" length="100" />

</class>
</hibernate-mapping>

...and the Annotation class mapping xml is:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Database.Core.Annotation,Database" table="Annotation">

<id name="Annotationid" column="ANNOTATIONID" type="Int32" unsaved-value="0">
<generator class="native"/>
</id>
<property column="ANNOTATION" type="String" name="Annotation" length="1000" />
<property column="CREATION_TIME_UTC" type="DateTime" name="CreationTimeUtc" not-null="true" />
<property column="MODIFIED_TIME_UTC" type="DateTime" name="ModifiedTimeUtc" not-null="true" />
<many-to-one name="RecordingDetailId" column="RECORDING_DETAIL_ID" class="Database.Core.RecordingDetails,Database" />
<many-to-one name="CreationTimeZoneId" column="CREATION_TIME_ZONE_ID" class="Database.Core.TimeZone,Database" />
<many-to-one name="ModifiedTimeZoneId" column="MODIFIED_TIME_ZONE_ID" class="Database.Core.TimeZone.Database" />

</class>
</hibernate-mapping>

Now my problem is I can't get the column key from the 2 Collection (Bag) objects which has the Owner set to TimeZone and the element 'ReturnedClass' to Annotation. The Key property of the Collection object is always null.

How can I get the collection key?? Has it anything to do with the fact that the collections are marked as "inverse"? If yes, how could I get the collection key without changing anything in the mapping files?

Thanks,
Bogdan

Hello again,

no answer, nobody knows or is it such a stupid question as it doesn't worth the effort?


Well, meantime I found that if I get the CollectionMappings list after the session is opened, the Key property (or getKey () in Hibernate) is no more null. Below are the lines I used, I need a sorted list of these collections, that's why I copy the CollectionMapping list in a sorted list.

(I use NHibernate, I forgot to mention, and the NHibernate 2.0 library)

<<
ISession s = SessionFactory.OpenSession();

m_sortedCollectionsByChildName = new List<Collection>(Config.CollectionMappings);

(m_sortedCollectionsByChildName as List<Collection>).Sort(new CollectionByChildComparer());

s.Close();
>>

If I remove the first and last lines (opening and closing the session), the Key property of every Collection object in the Config.CollectionMappings list is null. (the Config object is initialized as "new Configuration().Configure();")

Does anybody knows why the session must be opened in order to have the Collection.Key property not null? This way an extra time is introduced to connect to the session. CollectionMappings list should be part of metadata so it shouldn't have to connect to the session in order to create this property.


Thanks,
Bogdan

I suppose you have t build the session factory before you can access the meta information. Probably this is done implicitly in the OpenSession() call.

Thanks for the tip,

Yes, finally it turned up that the session factory had to be build in order for that Key member to be not null. So not the session be opened but just the session factory be created (which, of course was created when I opened the session in my previous approach).

Anyways, all the other meta informations are available if I just use the new Configuration().Configure().CollectionsMapping, without creating the session factory first.
It's just the "TableCollection" and "Key" properties of every Collection object from the CollectionsMapping that are null if the session factory is not created before. Strange, maybe it's a bug, or has something to do with the "inverse" bag.


Thanks,
Bogdan