Fluent Nhibernate: key-referencing an entity with a compositeId

Question

I'm experiencing issues with Fluent Nhibernate in mapping these relations:

Request entity:

• id
• date

School entity:

• Composite id made of
  • name
  • request
• property

Location entity:

• Composite id made of
  • exists (boolean)
  • school (-> foreign key on school_name and request_id)
• province

Basically, these relations represent a situation where I ask about a school to some web api service. I want to save the request (I put here only the date, but I have a LOT more fields) AND the information retrieved for the school. I also want to bind this information with the request which generated the information. I also want to save the school location and bind this information as before.

What I've done so far:

School.cs:

public class School
{
    public virtual string name {get; set;}
    public virtual Request request {get; set;}
    public virtual string property;
}

Request.cs:

public class Request
{
   public virtual int id {get; set;}
   public virtual DateTime date {get; set;}
}

Location.cs:

public class Location
{
    public virtual bool exist {get; set;}
    public virtual School school {get; set;}
    public virtual string province {get; set;}
}

SchoolMap.cs

public class SchoolMap : ClassMap<School>
{
    public SchoolMap() {
        CompositeId().KeyProperty(x => x.name, "name")
                     .KeyProperty(x => x.request, "request_id");
        Map(x => x.property);
    }
}

RequestMap.cs

public class Request : ClassMap<Request>
{
    public SchoolMap() {
        Id(x => x.id).GeneratedBy.Identity();
        Map(x => x.date);
    }
}

LocationMap.cs

public class LocationMap : ClassMap<Location>
{
    public LocationMap() {
        CompositeId().KeyProperty(x => x.exist)
                     .KeyReference(x => x.school, new string[] {"name", "request_id"});

        References<School>(x => x.school).Columns(new string [] {"name", "request_id"}).Cascade.All();
        Map(x => x.province);
    }
}

I also have implemented each repository inheriting from AbstractRepository. The "save" method is (example for SchoolRepository)

public School saveSchool(School school)
{
    var transaction = openTransaction();
    session.saveOrUpdate(school);
    transaction.commit();
    return school;
}

This scheme doesn't work. If I create and save (in this order) one request, then one school referencing that request, then one location referencing the school, I receive an "SqlParameter OutOfBound" exception.

I can't figure out how to map this relation.

Thanks in advance to all.

Answer 1

I try to demonstrate some composite id releation.

    public class EntityA
    {
        public EntityA()
        {
            Id = new EntityAId();
        }

        public virtual EntityAId Id { get; protected set; }
    }

    public class EntityAMap : FluentNHibernate.Mapping.ClassMap<EntityA>
    {
        public EntityAMap()
        {
            CompositeId(t => t.Id).KeyProperty(t => t.Id).CustomType<int>();
        }
    }

    public class EntityB
    {
        private EntityA _EntityA;

        public EntityB()
        {
            Id = new EntityBId();
        }

        public virtual EntityBId Id { get; protected set; }

        public virtual int EntityA_Id { get { return Id.EntityA_Id; } protected set { Id.EntityA_Id = value; } }
        public virtual EntityA EntityA { get { return _EntityA; } set { _EntityA = value; EntityA_Id = value == null ? 0 : value.Id.Id; } }
    }

    public class EntityBMap : FluentNHibernate.Mapping.ClassMap<EntityB>
    {
        public EntityBMap()
        {
            CompositeId(t => t.Id).KeyProperty(t => t.Id).CustomType<int>()
                                  .KeyProperty(t => t.EntityA_Id).CustomType<int>();

            Map(t => t.EntityA_Id).Not.Insert().Not.Update();
            References(t => t.EntityA).Columns("EntityA_Id");
        }
    }

    public class EntityAId
    {
        public virtual int Id { get; set; }

        public override bool Equals(object obj)
        {
            if (obj == null)
                return false;
            var t = obj as EntityAId;
            if (t == null)
                return false;
            if (Id == t.Id)
                return true;
            return false;
        }
        public override int GetHashCode()
        {
            return (Id).GetHashCode();
        }
    }

    public class EntityBId
    {
        public virtual int EntityA_Id { get; set; }
        public virtual int Id { get; set; }

        public override bool Equals(object obj)
        {
            if (obj == null)
                return false;
            var t = obj as EntityBId;
            if (t == null)
                return false;
            if (EntityA_Id == t.EntityA_Id && Id == t.Id)
                return true;
            return false;
        }
        public override int GetHashCode()
        {
            return (EntityA_Id + "|" + Id).GetHashCode();
        }
    }

Answer 2

public class EntityC
{
    private EntityA _EntityA;
    private EntityB _EntityB;

    public EntityC()
    {
        Id = new EntityCId();
    }

    public virtual EntityCId Id { get; protected set; }

    public virtual int EntityA_Id { get { return Id.EntityA_Id; } protected set { Id.EntityA_Id = value; } }
    public virtual EntityA EntityA { get { return _EntityA; } set { _EntityA = value; EntityA_Id = value == null ? 0 : value.Id.Id; } }

    public virtual int EntityB_Id { get { return Id.EntityB_Id; } protected set { Id.EntityB_Id = value; } }
    public virtual EntityB EntityB { get { return _EntityB; } set { _EntityB = value; EntityB_Id = value == null ? 0 : value.Id.Id; } }
}

public class EntityCMap : FluentNHibernate.Mapping.ClassMap<EntityC>
{
    public EntityCMap()
    {
        CompositeId(t => t.Id).KeyProperty(t => t.Id).CustomType<int>()
                              .KeyProperty(t => t.EntityA_Id).CustomType<int>()
                              .KeyProperty(t => t.EntityB_Id).CustomType<int>();

        Map(t => t.EntityA_Id).Not.Insert().Not.Update();
        References(t => t.EntityA).Columns("EntityA_Id");

        Map(t => t.EntityB_Id).Not.Insert().Not.Update();
        References(t => t.EntityB).Columns("EntityA_Id", "EntityB_Id");
    }
}
public class EntityCId
{
    public virtual int EntityA_Id { get; set; }
    public virtual int EntityB_Id { get; set; }

    public virtual int Id { get; set; }

    public override bool Equals(object obj)
    {
        if (obj == null)
            return false;
        var t = obj as EntityCId;
        if (t == null)
            return false;
        if (EntityA_Id == t.EntityA_Id && EntityB_Id == t.EntityB_Id && Id == t.Id)
            return true;
        return false;
    }
    public override int GetHashCode()
    {
        return (EntityA_Id + "|" + EntityB_Id + "|" + Id).GetHashCode();
    }
}