[DotNetDevelopment] Reading data from a database query

[Laura]

Hi,

I have a database query that I am reading data from into a form. I can
read one column into a listbox without any problems.
Where I get into difficulty is when I try to use the data read into
the listbox to get the related rows.

I keep getting the following error:

"Missing PrimaryKey Was Unhanled Exception"
"Table doesn't have a primary key"

The query has four fields and one of them is a primary key. Is reading
from queries very different to reading from tables??

Here is the code I have;

Dim objConnection As New OleDb.OleDbConnection( _
    "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= FYP.mdb")
Dim objAbsentNumberDA As New OleDb.OleDbDataAdapter("Select * from
NEWB", objConnection)
    Dim objAbsentNumberCB As New OleDb.OleDbCommandBuilder
(objAbsentNumberDA)
  Dim strNumber As String
    Dim StudentName As String
    Dim ClassName As String

then under the form load;

objAbsentNumberDA.MissingSchemaAction = MissingSchemaAction.AddWithKey
objDS.Clear()
objAbsentNumberDA.FillSchema(objDS, SchemaType.Source, "NEWB")
        objAbsentNumberDA.Fill(objDS, "NEWB")

  lstNumberAbsent.Items.Clear()
        FillNumberAbsent()
        FillNamesNeeded()

 Private Sub FillNumberAbsent()
        Dim i As Integer
        For i = 1 To objDS.Tables("NEWB").Rows.Count
            strNumber = objDS.Tables("NEWB").Rows(i - 1).Item
("Absent")
            lstNumberAbsent.Items.Add(strNumber)
        Next
    End Sub

    Private Sub FillNamesNeeded()
        Dim objRow2 As DataRow
        objRow2 = objDS.Tables("NEWB").Rows.Find(strNumber)
        StudentName = objRow2.Item("Student")

FillNumberAbsent() works fine. It's in FillNamesNeeded() that I get
the error at the line: objRow2 = objDS.Tables("NEWB").Rows.Find
(strNumber)

Am I doing something wrong, or has it something to do with the fact
that I'm using queries?

Thanks