Add Method (String, DataColumn[], DataColumn[])

ConstraintCollection.Add Method (String, DataColumn[], DataColumn[])

Constructs a new ForeignKeyConstraint, with the specified arrays of parent columns and child columns, and adds the constraint to the collection.

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

public Constraint Add (
	string name,
	DataColumn[] primaryKeyColumns,
	DataColumn[] foreignKeyColumns
public Constraint Add (
	String name, 
	DataColumn[] primaryKeyColumns, 
	DataColumn[] foreignKeyColumns
public function Add (
	name : String, 
	primaryKeyColumns : DataColumn[], 
	foreignKeyColumns : DataColumn[]
) : Constraint



The name of the ForeignKeyConstraint.


An array of DataColumn objects that are the primary key, or parent, columns.


An array of DataColumn objects that are the foreign key, or child, columns.

Return Value

A new ForeignKeyConstraint.

The CollectionChanged event occurs if the constraint is added successfully.

The following example creates two arrays of DataColumn objects, and then creates two ForeignKeyConstraint relationships between two tables in a dataset.

private void AddForeignConstraint(
    DataSet dataSet, DataTable table)
        DataColumn[] parentColumns = new DataColumn[2];
        DataColumn[] childColumns = new DataColumn[2];
        // Get the tables from the DataSet.
        DataTable customersTable = dataSet.Tables["Customers"];
        DataTable ordersTable = dataSet.Tables["Orders"];
        // Set Columns.
        childColumns[0] = ordersTable.Columns["CustomerID"];
        childColumns[1] = ordersTable.Columns["CustomerName"];
        // Create ForeignKeyConstraint
            parentColumns, childColumns);
    catch(Exception ex)
        // In case the constraint already exists, 
        // catch the collision here and respond.
        Console.WriteLine("Exception of type {0 occurred.", 

Windows 98, Windows 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 .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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