This abstract class represents a rule that can be placed on one or more DataColumn objects. ADO.NET includes two derived constraint classes: ForeignKeyConstraint and UniqueConstraint. Constraints aren’t enforced unless the EnforceConstraints property of the DataSet is true.

public abstract class Constraint {

// Protected Constructors

   protected Constraint( );

// Public Instance Properties

   public virtual string ConstraintName{set; get; } 

   public PropertyCollection ExtendedProperties{get; } 

   public abstract DataTable Table{get; }

// Protected Instance Properties

   protected internal virtual DataSet _DataSet{get; } 

// Public Instance Methods

   public override string ToString( );                          // overrides object

                  // Protected Instance Methods

   protected void CheckStateForProperty( );  

   protected internal void SetDataSet(DataSet dataSet);  



ForeignKeyConstraint, UniqueConstraint

Returned By

ConstraintCollection.{Add( ), this}

Passed To

ConstraintCollection.{Add( ), AddRange( ), CanRemove( ), IndexOf( ), Remove( )}

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