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ForeignKeyConstraint Constructor (DataColumn, DataColumn)

Initializes a new instance of the ForeignKeyConstraint class with the specified parent and child DataColumn objects.

Namespace:  System.Data
Assembly:  System.Data (in System.Data.dll)

'Declaration
Public Sub New ( _
	parentColumn As DataColumn, _
	childColumn As DataColumn _
)

Parameters

parentColumn
Type: System.Data.DataColumn

The parent DataColumn in the constraint.

childColumn
Type: System.Data.DataColumn

The child DataColumn in the constraint.

ExceptionCondition
ArgumentNullException

One or both of the columns is Nothing.

InvalidConstraintException

The columns have different data types.

-Or -

The tables don't belong to the same DataSet.

The following example creates a new ForeignKeyConstraint, sets some of its properties, and adds it to a DataTable object's ConstraintCollection.

' The next line goes into the Declarations section. 
' SuppliersProducts is a class derived from DataSet. 
Private suppliersProducts As SuppliersProducts 

Private Sub CreateConstraint()
   ' Declare parent column and child column variables. 
   Dim parentColumn As DataColumn
   Dim childColumn As DataColumn
   Dim fkConstraint As ForeignKeyConstraint

   ' Set parent and child column variables.
   parentColumn = _
       suppliersProducts.Tables("Suppliers").Columns("SupplierID")
   childColumn = _
       suppliersProducts.Tables("Products").Columns("SupplieriD")
   fkConstraint = New ForeignKeyConstraint(parentColumn, childColumn)

   ' Set various properties of the constraint. 
   With fkConstraint
      .ConstraintName = "suppierFKConstraint"
      .DeleteRule = Rule.SetNull
      .UpdateRule = Rule.Cascade
      .AcceptRejectRule = AcceptRejectRule.Cascade
   End With 

   ' Add the constraint, and set EnforceConstraints to true.
   suppliersProducts.Tables("Products").Constraints.Add(fkConstraint)
   suppliersProducts.EnforceConstraints = True 
End Sub

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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