Represents a constraint that can be enforced on one or more DataColumn objects.
Object
Constraint
[Visual Basic] MustInherit Public Class Constraint [C#] public abstract class Constraint [C++] public __gc __abstract class Constraint [JScript] public abstract class Constraint
A constraint is an automatic rule that determines the course of action when the value of a DataColumn is somehow altered. For example, when a value is deleted and the value is also used in one or more related tables, a ForeignKeyConstraint determines whether the values in the related tables are also deleted, set to null values, set to default values, or whether no action occurs. A UniqueConstraint, on the other hand, simply ensures that values in a table are unique.
Namespace: System.Data
Assembly: System.Data.dll