Oracle sequence.currval is not yet defined in this session

I'm trying to get a sequence.currval but get the 'sequence MY_SEQ.CURRVAL is not yet defined in this session' error.

I understand you have to call the sequence.nextval in sql plus before you can call sequence.currval but I'm unsure how to overcome this in a application.

Private Sub HeaderAdapter_RowUpdated(ByVal sender As Object, ByVal e As System.Data.OracleClient.OracleRowUpdatedEventArgs) Handles MyAdapter.RowUpdated
        Dim r As Integer
        Dim d As String

                Dim newCmd As New OracleClient.OracleCommand
                newCmd.Connection = Me.OraConn

                newCmd.CommandText = "Select export_seq.currval,to_char(sysdate,'yyyyddmm') as cdate from dual"
                Dim rdr As OracleClient.OracleDataReader = newCmd.ExecuteReader

                rdr = newCmd.ExecuteReader()
                While rdr.Read
                    r = CInt(rdr("CURRVAL"))
                    d = CStr(rdr("CDATE"))
                End While


                e.Row("ConsignmentID") = r
                e.Row("CDate") = d


            Catch ex As Exception
            End Try
End Sub
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Guy Hengel [angelIII / a3]Billing EngineerCommented:
You can use Sequence.currval only AFTER you used sequence.nextval in the same session (please refer to the oracle documentation about the sequence object)

Actually, you will use NEXTVALUE when inserting new records and NOT CURRVAL

newCmd.CommandText = "Select export_seq.nextval,to_char(sysdate,'yyyyddmm') as cdate from dual"

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