C# Nhibernate mapping to lookup table

Question

I'm having a difficult time mapping an entity to another entity that is a lookup table.

create table Sources
(
   SourceId identity(1,1) primary key not null,
   Name [nvarchar](255) NULL,
)


create table Candidates
(
   CandidateId int identity(1,1) primary key not null,
   SourceId int references Sources(SourceId) NULL,
)

And Enitites:

public class Candidate : Entity
{
    public virtual Source Source { get; set; }
}

public class Source : Entity
{
    public virtual string Name { get; set; }
}

I'm getting a error:

An association from the table Candidates refers to an unmapped class: Entities.Source

But I am unsure how to go about the mapping:

public class CandidateMap : IAutoMappingOverride<Candidate>
{
    public void Override(AutoMapping<Candidate> mapping)
    {
        mapping.Map(x => x.Source);
    }
}

Answer 1

The problem was I was inheriting from the Entity that was part of NHibernate namespace, instead of the SharpArch.NHibernate namespace. SharpArch does some mapping that the project I was working in was using.