NGWS SDK Documentation  

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DataRelation.ChildKeyConstraint

Gets the ForeignKeyConstraint for the relation.

[Visual Basic]
Overridable Public ReadOnly Property ChildKeyConstraint As _
   ForeignKeyConstraint
[C#]
public ForeignKeyConstraint ChildKeyConstraint {virtual get;}
[C++]
public: __property virtual ForeignKeyConstraint*
   get_ChildKeyConstraint();
[JScript]
public function get ChildKeyConstraint() : ForeignKeyConstraint;

Property Value

A ForeignKeyConstraint.

Example [Visual Basic]

The following example create a new ForeignKeyConstraint and assigns it to the ChildKeyConstraint property.

[Visual Basic]

Private Sub SetChildKeyConstraint()
   Dim dr As DataRelation
   Dim cCol As DataColumn
   Dim pCol As DataColumn
   ' Set child and parent columns.
   pCol = DataSet1.Tables("Suppliers").Columns("SupplierID")
   cCol = DataSet1.Tables("Products").Columns("SupplierID")
   dr = New DataRelation("SuppliersConstraint", pCol, cCol)
   ' Create ForeignKeyConstraint using the function below.
   Dim fk As ForeignKeyConstraint
   fk = CreateConstraint(pCol, cCol)
   ' Assign the constraint to the ChildKeyConstraint property
   dr.ChildKeyConstraint = fk
End Sub

Private Function CreateConstraint(pCol As DataColumn, cCol As DataColumn) _
   As ForeignKeyConstraint
   
   Dim myFKC As ForeignKeyConstraint
   myFKC = New ForeignKeyConstraint(pCol, cCol)
   ' Set null values when a value is deleted.
   myFKC.DeleteRule = Rule.SetNull
   myFKC.UpdateRule = Rule.Cascade
   myFKC.AcceptRejectRule = AcceptRejectRule.Cascade
   CreateConstraint = myFKC      
End Function

See Also

DataRelation Class | DataRelation Members | System.Data Namespace | AcceptRejectRule | ParentKeyConstraint | Rule