NHibernate - Mapping a String Foreign Key

Question

The legacy database I\'ve inherited contains the following tables:

Teams ( 
 TeamId INT PRIMARY KEY,
 Name VARCHAR(30)
)

Players (
 PlayerId INT PRIMARY KEY         


        

Answer 1

Now I'm not 100% sure if this will work but have you tried a many-to-one mapping relationship?

Maybe something like this:

<many-to-one name="Players" class="DataTransfer.Player, DataTransfer"
             column="Name" property-ref="Team" />

I believe that should work, according to the NHibernate manual property-ref is an attribute that is useed for mapping legacy data where a foreign key refers to a unique key of the associated table other than the primary key. This sounds like the situation you find yourself in.

Answer 2

I believe that you would need to use the property-ref attribute to define the field that you will be associating to. The foreign-key attribute is used to generate DDL to create the relationships (if you use that feature).

Answer 3

Just found this: https://nhibernate.jira.com/browse/NH-1272, seems this is a bug in NHibernate, and it is fixed in 2.1.0Alpha1.

I have tried it in NHibernate 2.1.0Alpha2, and it works!

(property-ref should only be in the map tag)

Answer 4

I think the property-ref attribute exists to solve this problem.

<bag name="Players">
   <key column="Team" property-ref="Team" />
   <one-to-many class="Player" property-ref="Team" />
</bag>