NHibernate Fluent Mapping a String Property to another Table's column

Question

I have a table in the database that is used only for holding some ID's descriptions:

TABLE SomeClass
- Columns
- ClassTypeID INT CONSTRAINT etc

TABLE SomeClassTypes
- ClassTypeID INT IDENTITY
- Description NVARCHAR

It's done like this so it's easy for users to insert/remove new types. I want to get a report of all of SomeClass , but I'd like to have a string property to hold the description from the other table:

public class SomeClass
{
    public virtual int SomeClassID { get; set; }
    public virtual int ClassTypeID { get; set; }
    public virtual string DescriptionType { get; set; }
}

public class SomeClassMap : ClassMapping<SomeClass>
{
    public SomeClassMap()
    {
        Table("SomeClassTable");
        Property(p => p.SomeClassID, map => 
        { 
            map.Column("SomeClassID");
            map.Generator(Generators.Identity);
        });
        Property(p => p.ClassTypeID, map => map.Column("ClassTypeID"));
        //Other properties here

        Property(p => p.DescriptionType, ?); //This line
    }
}

How can I do this?

Answer 1

Try to use joined table.

public class SomeClassMap : ClassMapping<SomeClass>
{
public SomeClassMap()
{
    Table("SomeClassTable");
    Property(p => p.SomeClassID, map => 
    { 
        map.Column("SomeClassID");
        map.Generator(Generators.Identity);
    });
    Property(p => p.ClassTypeID, map => map.Column("ClassTypeID"));
    //Other properties here

    Join("SomeClassTypes", m => 
        {
            m.KeyColumn("ClassTypeId");
            m.Fetch.Join();
            m.Map(x => x.DescriptionType).Column("Description");
        })
}
}

EDITED

If you use fluent mapping built in NHibernate, try this:

public class SomeClassMap : ClassMapping<SomeClass>
{
    public SomeClassMap()
    {
        Table("SomeClassTable");
        Property(p => p.SomeClassID, map => 
        { 
            map.Column("SomeClassID");
            map.Generator(Generators.Identity);
        });
        Property(p => p.ClassTypeID, map => map.Column("ClassTypeID"));
        //Other properties here

        Property(p => p.DescriptionType, ?); //This line
        Join("SomeClassTypes", m => 
            {
                m.Key(k => k.Column("ClassTypeId"));
                m.Fetch(FetchKind.Join);
                m.Property(x => x.DescriptionType).Column("Description");
            });
    }
}