How to map these redundant parent-child relationships using the Fluent API

Question

Any suggestions on how I can match this parent-child relationship twice, where the parent has a normal 1-to-many relationship (which works), but then I need a direct link 1: 1.0 from parent to specific child.

Public Class Source
    <Key()>
    Public Property SourceID As Int32

    Public Property SourceFields As List(Of SourceField)

    Public Property InboundMatchKeySourceFieldID As Nullable(Of Int32)
    Public Property InboundMatchKeySourceField As SourceField

and

Public Class SourceField
    <Key()>
    Public Property SourceFieldID As Int32

    Public Property SourceID As Int32

    Public Property Source As Source

This is a parent / child (working) mapping

    modelBuilder.Entity(Of Source).HasMany(
        Function(S) S.SourceFields
    ).WithRequired(
        Function(SF) SF.Source
    ).HasForeignKey(
        Function(SF) SF.SourceID
    )

This is my unsuccessful attempt for additional direct matching (not working):

modelBuilder.Entity(Of Source
    ).HasOptional(
        Function(S) S.InboundMatchKeySourceField
    ).WithRequired(
        Function(SF) SF.Source
    )

This gives me a "MetaDataException":

The specified schema is invalid. Errors: relation '_____. Source_InboundMatchKeySourceField 'was not loaded because the type' _____. SourceField 'is not available.

Answer 1

.WithRequired(...) ForeignKeyNavigationPropertyConfiguration. , EF .

, , :

modelBuilder.Entity(Of Source
).HasOptional(
    Function(S) S.InboundMatchKeySourceField
).WithRequired(
    Function(SF) SF.Source
) _
.Map(Function (x) x.MapKey("InboundMatchKeySourceFieldID"))

Answer 2

SourceField.Source .

Entity Framework:

• someSourceField.Source, , someSourceField thatSource.SourceFields, thatSource.InboundMatchKeySourceField , , ?
• , someSource.InboundMatchKeySourceField.Source != someSource?

---

, , , SourceFields.Contains(InboundMatchKeySourceField) thisSource.InboundMatchKeySourceField.Source == thisSource :

modelBuilder.Entity(Of Source
    ).HasOptional(
        Function(S) S.InboundMatchKeySourceField
    ).WithRequired()