I have a problem with a database that I don't control.

The database was written so that two fields/columns in certain tables identify a unique item.

As an example, consider having a student table and a class participant table. Rather than linking to a student number in the class participant table it links to the first name and surname fields.

Student

Student number
First Name
Surname

Class Participants

Class ID
First Name
Surname

(Please don't get bogged down on why you would do it like this, just accept that it has been done)

What I need to do is create a relationship in the Students.hbm.xml and ClassParticipants.hbm.xml files and I'm not sure how to do this.

The relationship would be one (Students) to many (Class Participants)

Any ideas?

Would it be possible for me to use a class?

For exemple, if I created a class called person that had a first name and a surname property could I use this in the set?

If so how do I reference it because as far as I can see you can only reference table columns?

You can bundle first and last name into a class, for example PersonName, change your objects to use a property of that class instead of the two name properties, and then use property-ref attribute of <many-to-one>. You need the PersonName class because you can't name two properties in property-ref.