This documentation is archived and is not being maintained.

DataColumn.Unique Property

Gets or sets a value that indicates whether the values in each row of the column must be unique.

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

property bool Unique {
	bool get ();
	void set (bool value);

/** @property */
public boolean get_Unique ()

/** @property */
public void set_Unique (boolean value)

public function get Unique () : boolean

public function set Unique (value : boolean)

Property Value

true if the value must be unique; otherwise, false. The default is false.

Exception typeCondition


The column is a calculated column.

As soon as this property is changed from false to true, a unique constraint will be created on this column to make sure that values are unique.

The following example creates new DataColumn, sets its properties, and adds it to a table's columns collection.

No code example is currently available or this language may not be supported.

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