"Not an association" using BreezeJS with special NHibernate mapping

Question

I am using Breeze with Web API and NHibernate. The following NHibernate mapping type (which is probably rarely used) leads to the Breeze error message "Not an association" in method MakeAssociationProperty of class NHMetadataBuilder:

<set name="Zugnummern"
     table="USER_ZUGNUMMER_T"
     lazy="true"
     cascade="save-update">
  <key column="USER_ID" />
  <element  column="TRAIN_NO"
      type="string"
      length="6"
      not-null="true"
      unique="false" />
</set>

How can I use Breeze with this special NHibernate mapping?

Answer 1

The exception "Not an association" would be prevented by checking whether collectionPersister is either ManyToMany or OneToMany in BreezeContextProvider.NH's NHMetadataBuilder.MakeAssociationProperty method because both conditions would be false for the above sample set mapping for property "Zugnummern":

// inverse foreign key
var collectionPersister = joinable as AbstractCollectionPersister;
if (collectionPersister != null)
{
      if (collectionPersister.IsManyToMany || collectionPersister.IsOneToMany)
      {
           // many-to-many relationships do not have a direct connection on the client or in metadata
           var elementPersister = collectionPersister.ElementPersister as AbstractEntityPersister;
           if (elementPersister != null)
           {
               fkNames = GetPropertyNamesForColumns(elementPersister, columnNames);
               if (fkNames != null)
                     nmap.Add("invForeignKeyNamesOnServer", fkNames);
           }
       }
}