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DataTable::Constraints Property

.NET Framework 3.5

Other Versions

Gets the collection of constraints maintained by this table.

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

Syntax

C++

JScript

public:
property ConstraintCollection^ Constraints {
	ConstraintCollection^ get ();
}

Property Value

Type: System.Data::ConstraintCollection
A ConstraintCollection that contains the collection of Constraint objects for the table. An empty collection is returned if no Constraint objects exist.

Remarks

A ForeignKeyConstraint restricts the action performed when a value in a column (or columns) is either deleted or updated. Such a constraint is intended to be used with primary key columns. In a parent/child relationship between two tables, deleting a value from the parent table can affect the child rows in one of the following ways.

The child rows can also be deleted (a cascading action).
The values in the child column (or columns) can be set to null values.
The values in the child column (or columns) can be set to default values.
An exception can be generated.

A UniqueConstraint becomes active when attempting to set a value in a primary key to a non-unique value.

Examples

The following example adds a ForeignKeyConstraint to the collection of constraints.

C++

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

Platforms

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.

Version Information