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ForeignKeyConstraint Constructor (String, DataColumn, DataColumn)

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

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

public ForeignKeyConstraint(
	string constraintName,
	DataColumn parentColumn,
	DataColumn childColumn
)

Parameters

constraintName
Type: System.String

The name of the constraint.

parentColumn
Type: System.Data.DataColumn

The parent DataColumn in the constraint.

childColumn
Type: System.Data.DataColumn

The child DataColumn in the constraint.

ExceptionCondition
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.

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

Private Sub CreateConstraint()
   ' Declare parent column and child column variables. 
   Dim parentColumn As DataColumn
   Dim childColumn As DataColumn
   Dim fkeyConstraint As ForeignKeyConstraint

   ' Set parent and child column variables.
   parentColumn = _
       suppliersProducts.Tables("Suppliers").Columns("SupplierID")
   childColumn = _
       suppliersProducts.Tables("Products").Columns("SupplierID")
   fkeyConstraint = New ForeignKeyConstraint( _
       "SupplierFKConstraint", parentColumn, childColumn)

   ' Set various properties of the constraint. 
   With fkeyConstraint
      .DeleteRule = Rule.SetNull
      .UpdateRule = Rule.Cascade
      .AcceptRejectRule = AcceptRejectRule.Cascade
   End With 

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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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