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RecordCount

property RecordCount: Integer read;

Example​

procedure ReadCount(const Data: TvxClientDataSet; var Count: Integer);
begin
  if Data.Active then
    Count := Data.RecordCount
  else
    Count := 0;
end;

Usage​

RecordCount returns the dataset's record count, which may represent fetched rows rather than the final source-query total.

  • Check Active and do not assume every TDataSet supports a nonnegative count.
  • Do not call Last merely for counting unless full-fetch cost is accepted.
  • Count is not a business aggregate from the database and can become stale after mutations.

Additional Technical Info​

RecordCount is declared by hidden ancestor TDataSet and is normally used through a visible descendant such as TvxClientDataSet. The base class cannot provide a universal count.

Source-backed behaviour​

Modified base TDataSet.GetRecordCount returns -1. TCustomClientDataSet requires Active and obtains the count from its DS cursor; provider details not yet fetched can affect availability/completeness. Generic descendants may fetch lazily, and calling Last can force remaining rows.

TvxClientDataSet configures FetchOnDemand=False and PacketRecords=-1, so its successful normal Open typically materializes the complete result and RecordCount reflects those client rows. Local filters can alter visible cursor behaviour; count semantics remain descendant/filter dependent.

IsEmpty checks current-buffer emptiness. FieldCount counts columns, not rows.

Official RTL references​

Created 2026-07-15