I'm stuck with the following problem : I would like to be able to disconnect a dataset from the database but be able to modify it locally (and I don't need to propagate modifications back to DB).

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I'm stuck with the following problem : I would like to be able to disconnect a dataset from the database but be able to modify it locally (and I don't need to propagate modifications back to DB).
This sounds like TClientDataset Briefcase model but I can't get it to work . Any idea why ?

Var
  Qu             : TAdsQuery;
  cdsData          : TClientDataSet;
  DataSetProvider: TDataSetProvider;
Begin
  cdsData := TClientDataSet.Create(self);
  Qu := TAdsQuery.Create(self);
  Qu.AdsConnection := AdsConnection1;
  Qu.SQL.Add('SELECT * FROM MYTABLE WHERE CRITERIA='something');
  Qu.Open;
  DataSetProvider := TDataSetProvider.Create(Nil);
  DataSetProvider.DataSet := Qu;
  cdsData.SetProvider(DataSetProvider);
  cdsData.Open;
  Qu.Close;

  cdsData.First;
  cdsData.Edit;
  i := 1;
  While Not cdsData.eof Do
    Begin
      If i Mod 2 = 0 Then // modify only even rows , for test
        cdsData.FieldByName('ID_PARAMETRAGE').AsInteger := 0;  // EDatabase error here : not in edit or insert mode

      Inc(i);
      cdsData.Next;
    End;
  cdsData.Close;
  cdsData.Free;
  Qu.Free

Comments

  1. Ondrej KelleJanuary 24, 2013 at 3:32 AM

    As the error says, you need to be in edit mode to edit the dataset. cdsData.Edit; ... cdsData.Post;

    ReplyDelete
  2. Olivier SCHWABJanuary 24, 2013 at 3:44 AM

    I have a cdsData.Edit .... Just after cdsData.First;

    ReplyDelete
  3. Olivier SCHWABJanuary 24, 2013 at 3:48 AM

    Oh OK , got it !  thanks Ondrej Kelle  !!! I need to put Edit and post around my update.

    ReplyDelete
  4. Ondrej KelleJanuary 24, 2013 at 3:49 AM

    Put it inside the loop. Navigating away from the current record (Next) cancels or auto-posts the edit and puts the dataset back in browse mode.

    ReplyDelete
  5. Olivier SCHWABJanuary 24, 2013 at 3:49 AM

    Corrected version :

    Var
      Qu             : TAdsQuery;
      cdsData          : TClientDataSet;
      DataSetProvider: TDataSetProvider;
    Begin
      cdsData := TClientDataSet.Create(self);
      Qu := TAdsQuery.Create(self);
      Qu.AdsConnection := AdsConnection1;
      Qu.SQL.Add('SELECT * FROM MYTABLE WHERE CRITERIA='something');
      Qu.Open;
      DataSetProvider := TDataSetProvider.Create(Nil);
      DataSetProvider.DataSet := Qu;
      cdsData.SetProvider(DataSetProvider);
      cdsData.Open;
      Qu.Close;

      cdsData.First;
      i := 1;
      While Not cdsData.eof Do
        Begin
          If i Mod 2 = 0 Then // modify only even rows , for test
     begin
       cdsData.Edit();
            cdsData.FieldByName('ID_PARAMETRAGE').AsInteger := 0;  /// EDatabase error here : not in edit or insert mode
    cdsData.Post();
     end;

          Inc(i);
          cdsData.Next;
        End;
      cdsData.Close;
      cdsData.Free;
      Qu.Free

    ReplyDelete

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