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ForeignKeyConstraint.ForeignKeyConstraint(String, DataColumn[], DataColumn[]) Constructor

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

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

public ForeignKeyConstraint (
	string constraintName,
	DataColumn[] parentColumns,
	DataColumn[] childColumns
public ForeignKeyConstraint (
	String constraintName, 
	DataColumn[] parentColumns, 
	DataColumn[] childColumns
public function ForeignKeyConstraint (
	constraintName : String, 
	parentColumns : DataColumn[], 
	childColumns : DataColumn[]
Not applicable.



The name of the ForeignKeyConstraint. If a null reference (Nothing in Visual Basic) or empty string, a default name will be given when added to the constraints collection.


An array of parent DataColumn in the constraint.


An array of child DataColumn in the constraint.

Exception typeCondition


One or both of the columns is a null reference (Nothing in Visual Basic).


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.

Private Sub CreateConstraint(ByVal suppliersProducts As DataSet)
    ' Declare parent column and child column variables.
    Dim parentColumns(1) As DataColumn
    Dim childColumns(1) As DataColumn
    Dim fkConstraint As ForeignKeyConstraint

    ' Set parent and child column variables.
    parentColumns(0) = _
    parentColumns(1) = _
    childColumns(0) = _
    childColumns(1) = _
    fkConstraint = New ForeignKeyConstraint( _
        "ProductSalesOrders", parentColumns, childColumns)

    ' Set various properties of the constraint.
    With fkConstraint
        .DeleteRule = Rule.SetDefault
        .UpdateRule = Rule.Cascade
        .AcceptRejectRule = AcceptRejectRule.Cascade
    End With

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

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0