System.Data Namespace

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Represents a restriction on a set of columns in which all values must be unique.

UniqueConstraint Class Members

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Constructors Visibility Constructor Parameters public UniqueConstraint ( String name , DataColumn column ) public UniqueConstraint ( DataColumn column ) public UniqueConstraint ( String name , DataColumn columns ) public UniqueConstraint ( DataColumn columns ) public UniqueConstraint ( String name , String columnNames , Boolean isPrimaryKey ) public UniqueConstraint ( String name , DataColumn column , Boolean isPrimaryKey ) public UniqueConstraint ( DataColumn column , Boolean isPrimaryKey ) public UniqueConstraint ( String name , DataColumn columns , Boolean isPrimaryKey ) public UniqueConstraint ( DataColumn columns , Boolean isPrimaryKey )   Properties Visibility Name Value Type Accessibility public Columns DataColumn [ Get ] public IsPrimaryKey Boolean [ Get ] public Table DataTable [ Get ]   Methods Visibility Name Parameters Return Type public Equals ( Object key2 ) Boolean public GetHashCode ( ) Int32

The UniqueConstraint is enforced on a single column ( or columns ) to ensure that a primary key value is unique.

Constraints are not enforced unless the EnforceConstraints property is set to true.

When a DataSet is merged with a second DataSet, constraints are not enforced until all merges are completed.

The following example adds a UniqueConstraint to a DataSet and sets the EnforceConstraints property to true.

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Constraint   Constraints   ConstraintCollection   DataRelation   ForeignKeyConstraint

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