Map table with composite key / foreign key to that

Question

I am trying to map a table that has a composite key and map another table that references this table.

Assume these tables:

1. ITEMDELIVERY with relevant columns:
   1. ITEMDELIVERY_ID
   2. DELIVERY_DATE
2. ITEMDELIVERYDETAIL with relevant columns:
   1. ITEMDELIVERYDETAIL_ID
   2. ITEMDELIVERY_ID
   3. PARTITIONDATE

The columns ITEMDELIVERY.ITEMDELIVERY_ID and ITEMDELIVERY.DELIVERY_DATE together form the PK.
The columns ITEMDELIVERYDETAIL.ITEMDELIVERY_ID and ITEMDELIVERYDETAIL.PARTITIONDATE form the FK from ITEMDELIVERYDETAIL to ITEMDELIVERY.

How do I map this?

I tried the following:

IAutoMappingOverride<ItemDeliveryDetail>:

mapping.References(x => x.ItemDelivery)
       .Columns("ITEMDELIVERY_ID", "PARTITIONDATE");

IAutoMappingOverride<ItemDelivery>:

mapping.CompositeId().KeyProperty(x => x.Id, "ITEMDELIVERY_ID")
                     .KeyProperty(x => x.DeliveryDate, "DELIVERY_DATE");

But this doesn't work, it results in a System.InvalidCastException: Invalid cast from 'DateTime' to 'Double'. when calling SaveOrUpdate on the session.

UPDATE:

I just checked the generated SQL and it shows that NHibernate somehow switches the values:

INSERT INTO ITEMDELIVERYDETAIL
       (ITEMDELIVERYDETAIL_ID,      AMOUNT, PROCESSED_BY_REM, SINGLE_ITEM_PRICE, 
        ITEMDELIVERY_ID, PARTITIONDATE, SupplierInvoice_id)
VALUES (hibernate_sequence.nextval, :p0,    :p1,              :p2,               
        :p3,             :p4,           :p5)
returning ITEMDELIVERYDETAIL_ID into :nhIdOutParam;

:p0 = 20.12.2011 16:29:44 [Type: Double (0)], 
:p1 = 6 [Type: DateTime (0)], 
:p2 = 21.12.2011 16:29:44 [Type: Double (0)], 
:p3 = 7 [Type: Int32 (0)], 
:p4 = 0 [Type: DateTime (0)], 
:p5 = 19.12.2011 16:29:44 [Type: Int32 (0)], 
:nhIdOutParam = 27638398 [Type: Int32 (0)]

As you can see, the parameters are a complete mess...
They should be like this:

:p0 = 6 [Type: Double (0)], 
:p1 = 21.12.2011 16:29:44 [Type: DateTime (0)], 
:p2 = 7 [Type: Double (0)], 
:p3 = 0 [Type: Int32 (0)], 
:p4 = 19.12.2011 16:29:44 [Type: DateTime (0)], 
:p5 = 27638398 [Type: Int32 (0)], 
:nhIdOutParam = NULL [Type: Int32 (0)]

Answer 1

I solved the problem. The reason for this strange behavior was that I had an explicit property PartitionDate that also was mapped (mapping.Map(x => x.PartitionDate).Column("PARTITIONDATE");).
This basically meant that the PARTITIONDATE column was mapped twice.