Private Sub addColumn()
        Dim sql As String
        Dim cmd As SqlClient.SqlCommand
 
        _conn.Open()
        sql = "ALTER TABLE Categories ADD KID uniqueidentifier"
        cmd = New SqlClient.SqlCommand(sql, _conn)
        Try
            cmd.ExecuteNonQuery()
        Catch ex1 As SqlClient.SqlException
            Debug.WriteLine(ex1.message)
            Return
        Finally
            _conn.Close()
        End Try
 
 
        sql = "SELECT CategoryID, KID FROM Categories"
        Dim da As New System.Data.SqlClient.SqlDataAdapter(sql, _conn)
        Dim dsGuid As New DataSet
        da.Fill(dsGuid, "Categories")
 
        For Each dr As DataRow In dsGuid.Tables("Categories").Rows
            dr("KID") = Guid.NewGuid
        Next
 
        Try
            Dim cb As New SqlCommandBuilder(da)
            da.Update(dsGuid, "Categories")
        Catch ex1 As SqlClient.SqlException
            Debug.WriteLine(ex1.Message)
        End Try
 
    End Sub