NGWS SDK Documentation  

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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.

[Visual Basic]
Overloads Public Sub New( _
   ByVal parentColumns() As DataColumn, _
   ByVal childColumns() As DataColumn _
)
[C#]
public ForeignKeyConstraint(
   DataColumn[] parentColumns,
   DataColumn[] childColumns
);
[C++]
public: ForeignKeyConstraint(
   DataColumn* parentColumns[],
   DataColumn* childColumns[]
);
[JScript]
public function ForeignKeyConstraint(
   parentColumns : DataColumn[],
   childColumns : DataColumn[]
);

Parameters

parentColumns
An array of parent DataColumn in the constraint.
childColumns
An array of child DataColumn in the constraint.

Exceptions

Exception Type Condition
ArgumentNullException One or both of the columns is a null reference (in Visual Basic Nothing).
InvalidConstraintException The columns have different data types.

-Or-

The tables don't belong to the same DataSet.

Example [Visual Basic]

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

[Visual Basic]

' The next line goes into the Declarations section of the module:
' SuppliersProducts is a class derived from DataSet.
Private myDataSet As SuppliersProducts 


Private Sub CreateConstraint()
   ' Declare parent column and child column variables.
   Dim pCols(1) As DataColumn
   Dim cCols(1) As DataColumn
   Dim myFKC As ForeignKeyConstraint
   ' Set parent and child column variables.
   pCols(0) = MyDataSet.Tables("OrderDetails").Columns("OrderID")
   pCols(1) = MyDataSet.Tables("OrderDetails").Columns("ProductID")
   cCols(0) = MyDataSet.Tables("Sales").Columns("OrderID")
   cCols(1) = MyDataSet.Tables("Sales").Columns("ProductID")
   myFKC = New ForeignKeyConstraint(pCols, cCols)
   ' Set various properties of the constraint.
   With myFKC
      .RelationName = "ProductSalesOrders"
      .DeleteRule = Rule.SetDefault
      .UpdateRule = Rule.Cascade
      .AcceptRejectRule = AcceptRejectRule.Cascade
   End With
   ' Add the constraint, and set EnforceConstraints to true.
   myDataSet.Tables("OrderDetails").Constraints.Add myFKC
   myDataSet.EnforceConstraints = True
End Sub

See Also

ForeignKeyConstraint Class | ForeignKeyConstraint Members | System.Data Namespace | ForeignKeyConstraint Constructor Overload List