Entity Framework - strange problem with multiple foreign keys mapped to one table

Question

I use EF (Framework 3.5 SP1) and create a simple demonstration of two tables:

Candidates

• int id
• request-pref-lang-coorepondence int (FK to CodeLanguages)
• application-pref-lang-exam int (FK to CodeLanguages)
• request-pref-lang-interview int (FK for CodeLanguages)

CodeLanguages

• code-lang-id int
• code-lang-desc varchar

CodeLanguage Entries May Have 0, 1, * Applicants

In each language indicated in the application, 1 (and only one) must be indicated. Link to CodeLanguage.

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Answer 1

. EF Microsoft , EF 3.5 SP1:

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: Partial Class Applicants , code_ids:

Private _intPrefCoorespLanguage As Integer = 0

Private _intPrefInterviewLanguage As Integer = 0

Private _intPrefExamLanguage As Integer = 0

<System.Runtime.Serialization.DataMemberAttribute()> _
Public Property MyPrefCoorespLanguageCodeId() As Integer
    Get
        Return (_intPrefCoorespLanguage)
    End Get
    Set(ByVal value As Integer)
        _intPrefCoorespLanguage = value
    End Set
End Property

<System.Runtime.Serialization.DataMemberAttribute()> _
Public Property MyPrefInterviewLanguageCodeId() As Integer
    Get
        Return (_intPrefInterviewLanguage)
    End Get
    Set(ByVal value As Integer)
        _intPrefInterviewLanguage = value
    End Set
End Property

<System.Runtime.Serialization.DataMemberAttribute()> _
Public Property MyPrefExamLanguageCodeId() As Integer
    Get
        Return (_intPrefExamLanguage)
    End Get
    Set(ByVal value As Integer)
        _intPrefExamLanguage = value
    End Set
End Property


<OnSerializing()> _
Private Sub PopulateClientProperties(ByVal sc As StreamingContext)
    Me.MyPrefCoorespLanguageCodeId = Me.PrefCoorespLanguage.code_lang_id
    Me.MyPrefInterviewLanguageCodeId = Me.PrefInterviewLanguage.code_lang_id
    Me.MyPrefExamLanguageCodeId = Me.PrefExamLanguage.code_lang_id
End Sub

: . code_id xaml

-: , :

myContext = New HR2009Entities

'Get original Applicant and feed in changes from detatched updated Applicant object
Dim OrigApp = (From a In myContext.Applicants Where a.applicant_id = pobjUpdatedApplicant.applicant_id Select a).First

'Apply preferred language foreign key refs
OrigApp.PrefCoorespLanguageReference.EntityKey = _
   New EntityKey("HR2009Entities.CodeLanguages", "code_lang_id",pobjUpdatedApplicant.MyPrefCoorespLanguageCodeId)

OrigApp.PrefInterviewLanguageReference.EntityKey = _
   New EntityKey("HR2009Entities.CodeLanguages", "code_lang_id", pobjUpdatedApplicant.MyPrefInterviewLanguageCodeId)

OrigApplicant.PrefExamLanguageReference.EntityKey = _
   New EntityKey("HR2009Entities.CodeLanguages", "code_lang_id", pobjUpdatedApplicant.MyPrefExamLanguageCodeId)

'Apply Applicant table native-field changes
myContext.ApplyPropertyChanges(OrigApp.EntityKey.EntitySetName, pobjUpdatedApplicant)

'Save to database
myContext.SaveChanges()

myContext.Dispose()

Answer 2

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, (alexj) @microsoft.com.

Entity Framework Team