Mapping relations to non-primary keys

In legacy databases, sometimes data is stored in ways that doesn't quite map to an object model. One such scenario is when the relation between for example a Customer and its ContactPersons is controlled by a column other than the primary key in the Customer table. NHibernate provides a way to handle these relations, using the property-ref mapping attribute.

Getting ready

Complete the Getting ready instructions at the beginning of this chapter.

How to do it…

1. Add a new folder named PropertyRefs to the MappingRecipes project.

2. Add a class named Customer to the folder:

   using System.Collections.Generic;
   
   namespace MappingRecipes.PropertyRefs
   {
     public class Customer
     {
       public Customer()
       {
         ContactPersons=new HashSet<ContactPerson>();
       }
       public virtual int Id { get; protected set; }
       public virtual string Name { get; set; }
       public virtual ISet<ContactPerson> ContactPersons 
    { 
      get; 
      set; 
    }
       public virtual int...