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ForeignKeyConstraint Constructor (DataColumn(), DataColumn())

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

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

'Declaration
Public Sub New ( _
	parentColumns As DataColumn(), _
	childColumns As DataColumn() _
)

Parameters

parentColumns
Type: System.Data.DataColumn()

An array of parent DataColumn in the constraint.

childColumns
Type: System.Data.DataColumn()

An array of 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 parentColumns(1) As DataColumn
   Dim childColumns(1) As DataColumn
   Dim fkConstraint As ForeignKeyConstraint

   ' Set parent and child column variables.
   parentColumns(0) = _
       suppliersProducts.Tables("OrderDetails").Columns("OrderID")
   parentColumns(1) = _
       suppliersProducts.Tables("OrderDetails").Columns("ProductID")
   childColumns(0) = _
       suppliersProducts.Tables("Sales").Columns("OrderID")
   childColumns(1) = _
       suppliersProducts.Tables("Sales").Columns("ProductID")
   fkConstraint = _
       New ForeignKeyConstraint(parentColumns, childColumns)

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

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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0
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