How to: Restrict a Data Column to Contain Unique Values
.NET Framework 2.0
You set a DataColumn to contain unique values by adding a unique constraint to a data table. Unique constraints are also called keys. Marking a column as a Primary Key in the Dataset designer will create a Unique Constraint. For more information, see How to: Set a Data Column as the Primary Key.
To constrain a column to contain unique values
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Open your dataset in the Dataset Designer.
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Right-click the column you want to constrain to unique values. Point to Add, and then click Key.
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Verify that the correct column is selected in the Unique Constraint dialog box.
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Replace the default name of the constraint with a more meaningful name, if desired. For more information, see Unique Constraint Dialog Box.
See Also
Tasks
How to: Set a Data Column as the Primary KeyWalkthrough: Displaying Data on a Form in a Windows Application
How to: Connect to Data in a Database
How to: Set the Data Type of a DataColumn
How to: Change the Caption of a DataColumn
How to: Add Columns to a DataTable
How to: Create an Autonumber DataColumn
Reference
DataTableConcepts
What's New in DataDataset Designer