I everybody:
I'm developing an app using Oracle 10g as DataBase Manager.
I have a many to many ralationship between a Document table and Move table.

I use the following mapping to each table(Document, Move and Document-Move)

The Document:

<class name="WindowsApplication.Document.Doc, WindowsApplication.Document" table="Documents">
<id name="Id" type="Int32">
<column name="ID" />
<generator class="sequence">
<param name="sequence">SEQ_DOCS</param>
</generator>
</id>
<set name="DocMoves" inverse="true" lazy="true">
<key>
<column name="IDDoc" not-null="true" />
</key>
<one-to-many class="WindowsApplication.Document.DocMove, WindowsApplication.Document" />
</set>
</class>

The Move:

<class name="WindowsApplication.Document.Move, WindowsApplication.Document" table="Moves">
<id name="Id" type="Int32">
<column name="ID" />
<generator class="sequence">
<param name="sequence">SEQ_Moves</param>
</generator>
</id>
<set name="DocMoves" inverse="true" lazy="true">
<key>
<column name="IDMove" not-null="true" />
</key>
<one-to-many class="WindowsApplication.Document.DocMove, WindowsApplication.Document" />
</set>
</class>

The Document-Move table:
<class name="WindowsApplication.Document.DocMove, WindowsApplication.Document" table="Document-Move" >
<composite-id name="Id" class="WindowsApplication.Document.DocMoveId, WindowsApplication.Document">

<key-property name="IdDoc" type="Int32">
<column name="IDDoc" />
</key-property>

<key-property name="IdMove" type="Int32">
<column name="IDMove" />
</key-property>

</composite-id>

<many-to-one name="Move" class="WindowsApplication.Document.Move, WindowsApplication.Document" update="false" insert="false" fetch="select">
<column name="IDMove" not-null="true" />
</many-to-one>

<many-to-one name="Doc" class="WindowsApplication.Document.Document, WindowsApplication.Document" update="false" insert="false" fetch="select">
<column name="IDDoc" not-null="true" />
</many-to-one>
</class>

The problem appears when I try to insert a new Doc, my app then generates a new Move, of course I have to insert a DocMove relation. But that is exactly what doesn't occur. I have tried everything, I even create a DocMove object and I assign the values but still doesn't work. In the database appears the Doc, the Move but the relation Document-Move is missing.
Any idea??? Are my mappings ok???

Hel please!!!!1

Looks like strangeness with inverse="true". The way you've set up your mapping, Document-Move is the "master", but won't create a Doc and a Move because you have insert/update = false. It's probable that you want to turn inverse="true" off for the DocMoves set in Document. That makes Document the "master": so long as you save the Move before the Document, the Document-Move will be created for you.

The reason I put the insert/update in false is because when I removed it I got an NHibernate error. Could you please explain me more about the inverse="true" . The way I see it the Master in the relation is the Doc. What changes should I do??? Is the composite-id ok???

Hi,

First of all what you did is a many-to-one-to-many mapping not many to many. If you are not expecting the link table to be added more attributes than use something like this:

<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
<class name="..Document" >
<id ... />

<set name="MoveSet" table="Document-Move" cascade="save-update" lazy="true" inverse="false">
<key column="IdDocument" />
<many-to-many class="...Move" column="IdMove" />
</set>
....
</class>
</hibernate-mapping>

When mapping the Move class the process is similar, just that the other set will be inverse=false.

I really don't recommend you using bag instead of set as the collection will be recreated at each update. If you really want the mapping to by many-one-many please reply and I will try to find you a solution. For this cases I always have an id for the link class as-well (any class has a simple id from my perspective) so my experience with composite id's is not notable..

Dragos

Oh, and by the way:

Setting inverse=true on a collection makes that collection unsensitive from updates from NHibernate point of view.

This is recommended approach because otherwise an insert in a collection would translate in an insert with null fk and an update on the fk (I may be mistaken though).

Anyway, this only affects wich association end handles updates/inserts but cascades are another thing, transitive persistence is still available (by this meaning the adding a transitive instance to a persistent collection that has at least cascade=save-update will imply that the transitive instance will become persistent too, and because inverse=true, this instance will be the one that will dictate the save).

Hope it helps,
Dragos