fluent nhibernate HasOne WithForeignKey not working

Question

Whenever I load a Task class, the Document property is always null, despite there being data in the db.

Task class:

public class Task {     public virtual Document Document { get; set; } 

Task Mapping override for AutoPersistenceModel:

public void Override(AutoMap<Task> mapping) {     mapping.HasOne(x => x.Document)         .WithForeignKey("Task_Id"); 

As you can see form what NHProf says is being run, the join condition is wrong, the WithForeignKey doesnt seem to take effect. In fact, i can write any string in the above code and it makes no difference.

FROM   [Task] this_     left outer join [Document] document2_     on this_.Id = document2_.Id 

It should be:

FROM   [Task] this_     left outer join [Document] document2_     on this_.Id = document2_.Task_Id 

If i hack the data in the db so that the ids match, then data is loaded, but obviously this is incorrect - but at least it proves it loads data.

Edit: rummaging in the fluent nhib source to find the XML produces this:

<one-to-one foreign-key="Task_Id" cascade="all" name="Document" class="MyProject.Document, MyProject, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />  

Edit: heres the schema:

CREATE TABLE [dbo].[Document]( [Id] [int] IDENTITY(1,1) NOT NULL, [Task_Id] [int] NOT NULL,  CREATE TABLE [dbo].[Task]( [Id] [int] IDENTITY(1,1) NOT NULL, 

Anyone got any ideas?

Thanks

Andrew

Answer 1

I ran into the same issue today. I believe the trick is not to use .ForeignKey(...) with the .HasOne mapping, but to use .PropertyRef(...) instead. The following is how I define a One-to-one relationship between an Organisation (Parent) and its Admin (Child):

HasOne(x => x.Admin).PropertyRef(r => r.Organisation).Cascade.All(); 

The Admin has a simple reference to the Organisation using its Foreign Key:

References(x => x.Organisation, "ORAD_FK_ORGANISATION").Not.Nullable(); 

When retrieving an Organisation, this will load up the correct Admin record, and properly cascades updates and deletes.

Answer 2

You should use:

References(x => x.Document, "DocumentIdColumnOnTask")