Listing A: Code That Uses IsNull() to Avoid 
Returning a NULL in the First Column

Dim cn As SqlConnection
Private Sub Form1_Load(ByVal sender As System.Object,  _
   ByVal e As System.EventArgs) Handles MyBase.Load
      Try
        cn = New SqlConnection("data source=betav9;database=PUBS;integrated
          security=sspi;")
            Dim cmd As New SqlCommand("SELECT NULL DateShipped, " _
            & " isNULL(Year_Born, -1), Author FROM Authors WHERE Author = @AW", cn)
            Dim drReader As SqlDataReader
            Dim da As New SqlDataAdapter(cmd)
            Dim ds As New DataSet()
        cmd.Parameters("@AW").Value = DBNull.Value
                                          ' Shows how to set a NULL parameter value.
            da.Fill(ds)                   ' To return a DataSet.
            cn.Open()
            drReader = cmd.ExecuteReader        ' Run the query and return a data stream.
            drReader.Read()                                ' Fetch the first row.