Basic Fluent NHibernate relationship issue - nhibernate

Question

The project that I am working on at the moment is using Entity Framework, however there are some issues that we have come across and therefore I am researching using NHibernate which we believe will sort out the majority of issues we have.
Anyway, I have been replicating a simple part of the system, but I have ran into what I assume is a very simple problem with a one-to-many relationship as it is giving very strange results.
Here are my entities:
public class Task : Base.Domain
{
private IList<TaskProperty> _taskProperties = new BindingList<taskProperty>();
private string _name = String.Empty;
private string _description = String.Empty;
public virtual IList<TaskProperty> TaskProperties
{
get
{
return _taskProperties;
}
set
{
if (_taskProperties == value) return;
_taskProperties = value;
OnNotifiyPropertyChanged("TaskProperties");
}
}
public virtual string Name
{
get
{
return _name;
}
set
{
if (_name == value) return;
_name = value;
base.OnNotifiyPropertyChanged("Name");
}
}
public virtual string Description
{
get
{
return _description;
}
set
{
if (_description == value) return;
_description = value;
base.OnNotifiyPropertyChanged("Description");
}
}
public Task()
: base()
{ }
}
public class TaskProperty : Base.Domain
{
private Task _task = null;
private string _name = string.Empty;
private string _description = string.Empty;
private int _propertyType = 0;
//public virtual int TaskID { get; set; }
public virtual Task Task
{
get
{
return _task;
}
set
{
if (_task == value) return;
_task = value;
OnNotifiyPropertyChanged("Task");
}
}
public virtual string Name
{
get
{
return _name;
}
set
{
if (_name == value) return;
_name = value;
OnNotifiyPropertyChanged("Name");
}
}
public virtual string Description
{
get
{
return _description;
}
set
{
if (_description == value) return;
_description = value;
OnNotifiyPropertyChanged("Description");
}
}
public virtual int PropertyType
{
get
{
return _propertyType;
}
set
{
if (_propertyType == value) return;
_propertyType = value;
OnNotifiyPropertyChanged("PropertyType");
}
}
public TaskProperty()
: base()
{ }
}
Here are my NHibernate mappings:
public class TaskMapping : ClassMap<Task>
{
public TaskMapping()
{
Id(x => x.Id).Column("RETTaskID");
Map(x => x.Name);
Map(x => x.Description);
Map(x => x.Version);
HasMany(x => x.TaskProperties).KeyColumn("RETTaskPropertyID");
Table("RETTask");
}
}
public class TaskPropertyMapping : ClassMap<TaskProperty>
{
public TaskPropertyMapping()
{
Id(x => x.Id).Column("RETTaskPropertyID");
Map(x => x.Name);
Map(x => x.Description);
Map(x => x.PropertyType);
References(x => x.Task).Column("RETTaskID");
Table("RETTaskProperty");
}
}
Note: The Domain class which these entities inherit from holds the ID (int Id).
The problem that I am facing is that when I get I Task from the database with an ID of 27 for example, I get the TaskProperty with an ID of 27 as well, not the expected 4 TaskProperties that are related to the Task via a foreign key.
This worked fine in Entity Framework and I know this is a simple situation for any ORM, so I assume I have set up my mappings incorrectly, but from all the examples I have found, I don't seem to be doing anything wrong!
Any answers/suggestions will be most welcome. Thanks.

Answer 1

You are almost there. The Column mapping for HasMany and References must be the same:
public TaskMapping()
{
...
HasMany(x => x.TaskProperties).KeyColumn("RETTaskID"); // use this
// HasMany(x => x.TaskProperties).KeyColumn("RETTaskPropertyID"); // instead of this
}
public TaskPropertyMapping()
{
...
References(x => x.Task).Column("RETTaskID");
}
The collection item has to have a reference column to the owner. This column is used for both directions, because that's how the reference in DB managed...