Fluent Nhibernate 1.0 - Specify foreign key constraint name between class and joined subclass

Question

I think this should be simple, but I can't figure out how to do it. Suppose I have the following maps:

public class AnimalMap : ClassMap<Animal> { Id( x => x.Id); }

public class CatMap: SubclassMap<Cat> {
    Extends<AnimalMap>();
    Map(x => x.IsDomestic);
}

Which creates tables as I expect:

Animal
------
Id

Cat
----
AnimalId : FK to Animal (named FK3500ABA0D)
IsDomestic

As noted, the FK gets generated by the db and ends up as FK3500ABA0D. All I want to do is set the name of that constraint, but I can't find how to do it via Fluent NHibernate (or actually even plain NHibernate, for that matter).

So, what am I missing?

Den

FNH 1.0 did not have the ability to name FKs. My accepted answer pertains to that version, but later versions should see the answer below. – Den

Answer 1

I don't know if FluentNH supports it, but the XML is simple:

<joined-subclass name="Cat">
  <key column="AnimalId" foreign-key="NameOfTheFK"/>
</joined-subclass>

Setup

Answer 2

Fluent NH does allow this:

public class ReferenceConvention : IReferenceConvention{
     public void Apply(IManyToOneInstance instance) {
          instance.ForeignKey(string.Format("FK_{0}_{1}",
               instance.EntityType.Name,
               instance.Name));
     }
}

You'd also need to implement IHasManyConvention and IHasManyToManyConvention in the same way as above.

Apteral

FYI, at the time the question was asked and answer that feature was not in FNH. I've updated the question and left a comment explaining why the accepted answer is not being changed. Thanks for your answer as well! – Den

Answer 3

I had the same problem, the following works well for me:

public class JoinedSubclassForeignKeyConvention : IJoinedSubclassConvention
{
    public void Apply(IJoinedSubclassInstance instance)
    {
        if (instance.Type.BaseType != null)
            instance.Key.ForeignKey(string.Format("FK_{0}_{1}", instance.EntityType.Name, instance.Type.BaseType.Name));
    }
}

Your foreign key constraint would then be named as FK_Cat_Animal

Pudding

Did this work with FNH 1.0 however? Later versions fixed the issue, but this question is about 1.0 specifically. – Den