Question

I cannot figure out how to configure my mappins with Fluent 🙁

Here is my situation:
I have an Element object, which (in theory) should have a one-to-one relationship with a Search object. However, the Search object should have a one-to-many relationship with itself.
In other words, an Element object can have at most 1 Search object (can also have none), and a Search object, has a collection of other Search objects.

I started with the following mappings. They create the correct DB model I expected and can save fine. Problems start when retrieving data…

public class ElementMap : ClassMap< Element >
{
    public ElementMap()
    {
        Schema( "dbo" );
        Table( "Element" );
        LazyLoad();
        Id( x => x.Id )
            .Column( "Id" )
            .CustomType( "Int32" )
            .Access.Property()
            .CustomSqlType( "int" )
            .Not.Nullable()
            .UnsavedValue( 0 )
            .GeneratedBy.Identity();
        HasOne( x => x.Search )
            .Cascade.All()
            .Not.LazyLoad();
    }
}

and

public class SearchMap : ClassMap< Search >
{
    public SearchMap()
    {
        Schema( "dbo" );
        Table( "Search" );
        LazyLoad();
        Id( x => x.Id )
            .Column( "Id" )
            .CustomType( "Int32" )
            .Access.Property()
            .CustomSqlType( "int" )
            .Not.Nullable()
            .UnsavedValue( 0 )
            .GeneratedBy.Identity();
        ReferencesAny( x => x.Parent )
            .IdentityType< int >()
            .MetaType< string >()
            .EntityTypeColumn( "ParentType" )
            .EntityIdentifierColumn( "ParentId" )
            .AddMetaValue< Element >( "E" )
            .AddMetaValue< Search >( "S" );
        HasMany( x => x.Searches )
            .Table( "Search" )
            .KeyColumn( "ParentId" )
            .Where( "ParentType = 'S'" )
            .Cascade.All()
            .LazyLoad();
    }
}

So as said, the model looks correct, the Element table contains 1 column for the ID, the Search table contains an ID column, a ParentType column set to “E” if the parent is an Element object and set to “S” if the parent is a Search object, and finally a ParentId that references the ID of the parent.

Somehow it seems to be fine and makes sense (at least to me :P).

Here’s a sample of the data in the database:

Element table
Id
-----------
1
2

Search table
Id          ParentType ParentId
----------- ---------- -----------
1           E          1
2           S          1
3           E          2
4           S          3
5           S          3

So here my first Element object contains a Search object that contains 1 Search object,
and the 2nd Element object contains a Search object that contains 2 search objects.

Now the problem is that when I retrieve data, the first Element object is correct, but the 2nd one isn’t. Its Search object is ID’d 2, where really it should be 3 (ID of the 2nd Search object whoses parent is marked as E in the database).

My guess is that I should somehow add a .Where( “ParentType = ‘E'” ) to the Element object mapping as I have done for the Search object, but there is no .Where() method on the HasOne() method (since it normally wouldn’t make sense to have one). So I really don’t know how to specify it… 🙁

I hope this is clear enough as problems are always quite hard to explain 🙂
Any help will be greatly appreciated since this is a pretty important project for me 🙁

Thanks all!

Seb 🙂

Answer 1

HasOne does not take into account the Any part of ReferenceAny hence it can’t be used here at all. The only Option i see is to map a private collection of searches with the appropriate where ParentType = 'E' and handle the conversion to a reference in the property Search.