NHibernate - Delete Not Peristing in the Database - nhibernate

Question

i'm trying to remove an item from a one to many list and have it persist in the database. Here are the entities i have defined:
public class SpecialOffer
{
public virtual int SpecialOfferID { get; set; }
public virtual string Title { get; set; }
public virtual IList<SpecialOfferType> Types { get; private set; }
public SpecialOffer()
{
Types = new List<SpecialOfferType>();
}
}
public class SpecialOfferType
{
public virtual SpecialOffer SpecialOffer { get; set; }
public virtual Type Type { get; set; }
public virtual int MinDaysRemaining { get; set; }
#region composite id requirements
public override bool Equals(object obj)
{
if (obj == null || !(obj is SpecialOfferType))
return false;
var t = (SpecialOfferType)obj;
return SpecialOffer.SpecialOfferID == t.SpecialOffer.SpecialOfferID && Type.TypeID == t.Type.TypeID;
}
public override int GetHashCode()
{
return (SpecialOffer.SpecialOfferID + "|" + Type.TypeID).GetHashCode();
}
#endregion
}
public class Type
{
public virtual int TypeID { get; set; }
public virtual string Title { get; set; }
public virtual decimal Price { get; set; }
}
With the following fluent mappings:
public class SpecialOfferMap : ClassMap<SpecialOffer>
{
public SpecialOfferMap()
{
Table("SpecialOffers");
Id(x => x.SpecialOfferID);
Map(x => x.Title);
HasMany(x => x.Types)
.KeyColumn("SpecialOfferID")
.Inverse()
.Cascade.All();
}
}
public class SpecialOfferTypeMap : ClassMap<SpecialOfferType>
{
public SpecialOfferTypeMap()
{
Table("SpecialOfferTypes");
CompositeId()
.KeyReference(x => x.SpecialOffer, "SpecialOfferID")
.KeyReference(x => x.Type, "TypeID");
Map(x => x.MinDaysRemaining);
}
}
public class TypeMap : ClassMap<Type>
{
public TypeMap()
{
Table("Types");
Id(x => x.TypeID);
Map(x => x.Title);
Map(x => x.Price);
}
}
The problem i have is that if i remove an item from the SpecialOffer.Types collection it successfully removes it from the list but when i try to save the session the change is not persisted in the database. I'm assuming this is something to do with the composite id on the join table since i have been able to do this successfully in the past with a standard id.
I'd appreciate it if someone could show me what i'm doing wrong. Thanks

Answer 1

I think you have to 1) Change the cascade setting on SpecialOffer.Types to Cascade.AllDeleteOrphan() and 2) set SpecialOfferType.SpecialOffer = null when you remove it from the collection. Since the collection is the inverse side of the relationship, the many-to-one reference to SpecialOffer on SpecialOfferType has to be set to null to make it an orphan, then Cascade.AllDeleteOrphan will cause it to be deleted.