ForeignKeyConstraint Constructor (DataColumn(), DataColumn())

.NET Framework (current version)

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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)

Syntax

C++

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.

Exceptions

Exception	Condition
ArgumentNullException	One or both of the columns is null.
InvalidConstraintException	The columns have different data types. -Or - The tables don't belong to the same DataSet.

Examples

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

Version Information

.NET Framework
Available since 1.1