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

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

 

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 System.Data.dll)

public ForeignKeyConstraint(
	string constraintName,
	DataColumn[] parentColumns,
	DataColumn[] childColumns
)

Parameters

constraintName
Type: System.String

The name of the ForeignKeyConstraint. If null or empty string, a default name will be given when added to the constraints collection.

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.

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.

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) = _
        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( _
        "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( _
        fkConstraint)
    suppliersProducts.EnforceConstraints = True
End Sub

.NET Framework
Available since 1.1
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