Question

The story:
I had class User and class Organization: User. I did not use any mappings for these classes, let FNH do mapping automatically. Then, I added

   public class OrganizationMap : IAutoMappingOverride<Organization>
   {
      public void Override(AutoMap<Organization> mapping)
      {
      }
   }

Notice there’re no overrides. So I did not expect any changes in FNH behavior. But I got this (during schema export actually):

NHibernate.MappingException:
(XmlDocument)(2,4): XML validation
error: The element ‘class’ in
namespace ‘urn:nhibernate-mapping-2.2’
has incomplete content. List of
possible elements expected: ‘meta,
subselect, cache, synchronize,
comment, tuplizer, id, composite-id’
in namespace
‘urn:nhibernate-mapping-2.2’.

The generated Orders.Core.Organization.hbm.xml was really empty:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="">
  <class name="Orders.Core.Organization, Orders.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" table="Organizations" xmlns="urn:nhibernate-mapping-2.2" />
</hibernate-mapping>

So, after I reviewed the User.hbm I got the idea – I need to override Organization in the base class like this:

   public class UserMap : IAutoMappingOverride<User>
   {
      public void Override(AutoMap<User> mapping)
      {
         mapping.JoinedSubClass<Organization>("ColumnId", m => {...}
         );
      }
   }

But, I would better like to do this in a separate mapping override class for Organization… after all, what would the mapping become if I have 5 subclasses all in single Override method.

Is this possible?

Answer 1

Turned out that with latest FNH (some revision after RC) this is possible now. I wonder if this is because I asked 😉

So I had this

 mapping.JoinedSubClass<Organization>("UserId", m =>
    {
       m.HasMany(x => x.Currencies).Element("Currency").AsBag();
    }
 );

and it stopped working after upgrading to RC. Then I moved this into its own class

   public class OrganizationMap : IAutoMappingOverride<Organization>
   {
      public void Override(AutoMapping<Organization> mapping)
      {
         mapping.HasMany(x => x.Currencies).Element("Currency").AsBag();
      }
   }

it started to work again. Just like I wanted! Now I don’t even need to indicate JoinedSubClass as this is the default, anyway. I can just override my subclass properties which is cool.

Though it wasn’t too easy to figure out why NH started to complain about association of strings… I even thought that .Element is broken in RC. I wonder why JoinedSubClass still has this mapping part if it doesn’t completely work.