Difference between the command APPLYUPDATES and COMMITUPDATE

[doidopb]

Hi...

I use version 6.6.2-RC Zeos with MYSQL 5.0.45. I have a TZQuery with the property Cached Updates = True.

It is recommended to use the command COMMITUPDATES after the command APPLYUPDATES, as shown below:

ZQuery1.ApplyUpdates;
ZQuery1.CommitUpdates;

If using only the command APPLYUPDATES the changes are recorded in the table.

So what is the function of the command COMMITUPDATES, after using the APPLYUPDATES????

Thanks

[EgonHugeist]

doidopb,

COMMITUPDATES clears the CachedUpdates buffer without applying the changes to the DataBase, AFAIK.

ApplyUpdates updates the edited rows and finally needs a Commit.

[doidopb]

I'm from Brazil, I'm sorry for bad English.

What I understood is that CommitUpdates only clears the buffer, without applying the changes.

Already ApplyUpdates writes the changes to the base and clears the buffer cachedupdates. That??

doidopb,

COMMITUPDATES clears the CachedUpdates buffer without applying the changes to the DataBase, AFAIK.

ApplyUpdates updates the edited rows and finally needs a Commit.

[doidopb]

My code is:

Code: Select all

procedure StartTransacao;
begin
  dtm_banco.z_transacao.SQL.Clear;
  dtm_banco.z_transacao.SQL.Text := 'START TRANSACTION';
  dtm_banco.z_transacao.ExecSQL;
end;

procedure CommitTransacao;
begin
  dtm_banco.z_transacao.SQL.Clear;
  dtm_banco.z_transacao.SQL.Text := 'COMMIT';
  dtm_banco.z_transacao.ExecSQL;
end;

procedure RollBackTransacao;
begin
  dtm_banco.z_transacao.SQL.Clear;
  dtm_banco.z_transacao.SQL.Text := 'ROLLBACK';
  dtm_banco.z_transacao.ExecSQL;
end;

procedure Tfrm_saidas.spb_confirmarClick(Sender: TObject);
begin
  ActiveControl := nil;
  if trim(edt_requisicao.Text) = '' Then
    begin
      ShowMessage('Preencha a requisicao');
      edt_requisicao.SetFocus;
    end
  else
  if edt_data.Text = '  /  /    ' Then
    begin
      ShowMessage('Preencha a data');
      edt_data.SetFocus
    end
   else
   if dtm_banco.z_sce1_saidas.RecordCount = 0 Then
    begin
      ShowMessage('Coloque ao menos 1 item nessa sa?da');
      edt_codigo.SetFocus;
    end
  else
   //--------------------------------------------------//
      begin
        StartTransacao;
        try
          dtm_banco.z_sce1_reqsaida.Post;
          dtm_banco.z_sce1_saidas.ApplyUpdates;
          dtm_banco.z_sce1_saidas.CommitUpdates;

          //atualizar o estoque @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
          dtm_banco.z_sce1_saidas.First;
          while not(dtm_banco.z_sce1_saidas.Eof) do
            begin
              //atualiza o estoque que est? em SCE1_ESTRECEP, diminuindo o mesmo, dado a saida
              dtm_banco.z_formulas.SQL.Text := 'UPDATE SCE1_ESTRECEP SET quant_nf = quant_nf - '+dtm_banco.z_sce1_saidasquantidade.AsString+','+
                                               'dt_ult_sai = CASE WHEN "'+FormatDateTime('yyyy/mm/dd',Date)+'" > dt_ult_sai THEN "'+
                                               FormatDateTime('yyyy/mm/dd',Date)+'" WHEN dt_ult_sai IS NULL THEN "'+
                                               FormatDateTime('yyyy/mm/dd',Date)+'" ELSE dt_ult_sai END WHERE codigo = "'+
                                               dtm_banco.z_sce1_saidascod_prod.AsString+'"';
              dtm_banco.z_formulas.ExecSQL;
              //**********************************************************

              //atualiza o estoque que est? em ESTOQRC, diminuindo o mesmo, dado a saida
              dtm_banco.z_formulas.SQL.Text := 'UPDATE ESTOQRC SET quant_nf = quant_nf - '+dtm_banco.z_sce1_saidasquantidade.AsString+
                                               ',dt_ult_sai = CASE WHEN "'+FormatDateTime('yyyy/mm/dd',Date)+'" > dt_ult_sai THEN "'+
                                               FormatDateTime('yyyy/mm/dd',Date)+'" WHEN dt_ult_sai IS NULL THEN "'+
                                               FormatDateTime('yyyy/mm/dd',Date)+'" ELSE dt_ult_sai END WHERE codigo = "'+
                                               dtm_banco.z_sce1_saidascod_prod.AsString+'"';
              dtm_banco.z_formulas.ExecSQL;
              //**********************************************************
              
              dtm_banco.z_sce1_saidas.Next;
            end;
          //@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

          EstadoNormal;
          CommitTransacao;

          if op = 'i' Then
            begin
              dtm_banco.z_sce1_reqsaida.SQL.Text := 'SELECT * FROM SCE1_REQSAIDA WHERE requisicao = "'+dtm_banco.z_sce1_reqsaidarequisicao.AsString+'"';
              dtm_banco.z_sce1_reqsaida.Close; dtm_banco.z_sce1_reqsaida.Open;
           end;
          AtualizaItens;
        except;
          RollbackTransacao;
          ShowMessage('Erro ao gravar os dados');
          Close;
        end;
      end;
end;

It is currently used the COMMIT UPDATES as i did??? Or is it not necessary??

[EgonHugeist]

doidopb,

the code seems to be right. Hint: have no clue about 6.6.x series.