Create Unique Constraint

UniqueConstraint Class represents a restriction on a set of columns in which all values must be unique.

Following example show how to create Unique Constraint

 

Sub Main()

        Dim objmyTable As DataTable = New DataTable

        objmyTable.Columns.Add("Id", GetType(Integer))

        objmyTable.Columns.Add("Name", GetType(String))

 

        Dim uniqueConstraint As Data.UniqueConstraint = New Data.UniqueConstraint("UniqueConstraint", objmyTable.Columns("Id"))

 

        objmyTable.Constraints.Add(uniqueConstraint)

        Try

            objmyTable.Rows.Add(132, "mukesh")

            objmyTable.Rows.Add(123, "vinay")

            objmyTable.Rows.Add(132, "ashish")

 

        Catch ex As Exception

            Console.WriteLine(vbLf & "Error: {0}", ex.Message)

        End Try

        Console.WriteLine(vbLf & "Press any key to continue.")

        Console.ReadLine()

    End Sub

Output :