PrimeMinister

1 hour ago, Dany Marmur said:

So fix the actual problem before asking/looking for a workaround.

Asking us to help you by-pass problem that you created it not constructive.

 

Oh, ah! Just realized i wrote an "heffernandic" post!

oh ok

3 hours ago, Vandrovnik said:

In your code, I cannot see initial setting of grid.RowCount.

I set RowCount to 2

Hey guys, so for this program I'm writing I want to check a string grid for empty rows/rows with just spaces in them and then subsequently deleting them to clean the grids up a bit.

I made a procedure that reads the fields from a specific table in a DB and into a corresponding string grid. While 13 of the 14 grids I have, read the records like they're supposed to from the DB, one single table doesn't read correctly, it reads the same amount of records again as empty rows when displayed on the grid.

For example, let's say I have 3 records in the table in the DB and I read it into the grid, the records display properly but then they add 3 more rows with just spaces in them.

My code for this so far:

procedure TfrmPuntehou.IncreaseRowCount(grid: TStringGrid);
begin
  //increases rows in grid
  grid.RowCount:= grid.RowCount+1;
end;

procedure TfrmPuntehou.WriteToList(tbl: TADOTable;grid:TStringGrid);
var
  Row: Integer;
  i: Integer;
begin

  tbl.Active:= True;

  Row := 1;

  // Populate cells
  Tbl.First;
  while not (Tbl.Eof) do
  begin
    grid.Cells[0,Row]:= IntToStr(Row);
    grid.Cells[1,Row]:= tbl.fields[0].AsString;
    grid.Cells[2,Row]:= tbl.fields[1].AsString;
    grid.Cells[3,Row]:= tbl.fields[2].AsString;
    Inc(Row);
    IncreaseRowCount(grid);
    Tbl.Next;
  end;
  tbl.Active:=false;

  //what I'm planning to do to alleviate this but I'm not sure to use in the conditions of the if
  // because if I say grid.Rows[i] = ''/grid.Rows[i] = ' ' then I get an error
//  for i := 1 to grid.RowCount - 1 do
//  begin
//    if () OR () then
//    begin
//      grid.Rows[i].Delete;
//    end;
//  end;
end;

Illustration of what I'm talking about:

What is supposed to happen:

What's happening (the records are inserted correctly, but there are unnecessary rows here for only 3 records. When exported to a CSV the empty rows are filled with spaces"):

Thanks in advance for any help on this!

Kind Regards

PrimeMinister

9 minutes ago, Mike Torrettinni said:

See similar question with accepted answer, perhaps it can help you: https://stackoverflow.com/questions/65821505/delphi-clearing-ado-tables

Thx, I solved my problem now and thx to @emailx45 for trying to help as well

😀

9 minutes ago, Anders Melander said:

Read the documentation or example some existing code that works.

 

The error message is pretty clear about what the problem is. I don't need to explain it to you.

ok thx

8 minutes ago, Anders Melander said:

MyCmd isn't initialized so that's probably the cause of the AV. You need to create an instance of TADOCommand or reference an existing instance. Get rid of the local var declaration if you meant to be using the TADOCommand with the same name on the form

 

Apart from that you haven't told us where in your code the problem occurs.

It was on this line

MyCmd.CommandText := 'Delete * from '+tablename;

So I changed my code to this:
   

//clears entire database
    with dmRacers do
    begin

      MyCmd := TADOCommand.Create(Self);
      try
      tbl1660.Active := true;

      MyCmd.CommandText := 'Delete * from tbl1660';
      MyCmd.Execute;

      tbl1660.Active := false;
        {EmptyTable(tbl1660,'tbl1660');
        EmptyTable(tblXKarts,'tblXKarts');
        EmptyTable(tblTwoPointOne,'tblTwoPointOnes');
        EmptyTable(tblMidB,'tblMidB');
        EmptyTable(tblMidA,'tblMidA');
        EmptyTable(tblLateModel,'tblLateModels');
        EmptyTable(tblSprints,'tblSprints');
        EmptyTable(tblV8,'tblV8');
        EmptyTable(tblHeavyMetals,'tblHeavyMetals');
        EmptyTable(tblHotrods,'tblHotrods');
        EmptyTable(tblPinkrods,'tblPinkrods');
        EmptyTable(tblStockrods,'tblStockrods');
        EmptyTable(tblMinis,'tblMinis');
        EmptyTable(tblDevelopment,'tblDevelopment');}
      finally
        MyCmd.Free;
      end;

But now the error is "Missing Connection or ConnectionString".

I don't know what to do anymore...

Hey guys, so I'm having a problem with my ADO Tables. I have a button in my program that is meant to clear all tables in the database related to the program when clicked but whenever I click it, it gives errors. (no matter how many times I change my code) Could it be a problem with my Data Module or what? (I'm not sure cause my button which saves stuff to the database, works perfectly without a hitch) How could I alleviate this?

Code of my data module:

   const
  scConnectionString = 'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=%pathtomdb%Racers.mdb;Mode=ReadWrite;Persist Security Info=False;';
var
  dmRacers: TdmRacers;

implementation

{%CLASSGROUP 'Vcl.Controls.TControl'}

{$R *.dfm}

procedure TdmRacers.DataModuleCreate(Sender: TObject);
var
path:string;
begin
  path:=ExtractFilePath(ParamStr(0));
  conToDB.ConnectionString := StringReplace(scConnectionString, '%pathtomdb%', path, []);
  conToDB.Connected:=True;
  tbl1660.Active := True;
  tblXKarts.Active := True;
  tblTwoPointOne.Active := True;
  tblMidB.Active := True;
  tblMidA.Active := True;
  tblLateModel.Active := True;
  tblSprints.Active := True;
  tblV8.Active := True;
  tblHeavyMetals.Active := True;
  tblHotrods.Active := True;
  tblPinkrods.Active := True;
  tblStockrods.Active := True;
  tblMinis.Active := True;
  tblDevelopment.Active := True;
end;

Code from the form:

 public
    { Public declarations }
    MyCmd:TADOCommand;
    procedure EmptyTable(tbl:TADOTable;tablename:string);
    procedure ResetActiveProp(tbl:TADOTable);
  end;

var
  frmEntry: TfrmEntry;

implementation

{$R *.dfm}

procedure TfrmEntry.ResetActiveProp(tbl: TADOTable);
begin
  tbl.Active := True;
end;

procedure TfrmEntry.EmptyTable(tbl: TADOTable; tablename: string);
var
  MyCmd: TADOCommand;
begin
    tbl.Active := true;

    MyCmd.CommandText := 'Delete * from '+tablename;
    MyCmd.Execute;

    tbl.Active := false;
end;

procedure TfrmEntry.bmbClearClick(Sender: TObject);
var
  i:integer;
begin
  cbxGridSelect.ItemIndex:=-1;
  cbxGridSelect.Text:='Select a class';
  edtRacerName.Clear;
  edtCarNumber.Clear;
  edtLicenseNum.Clear;
  i:=MessageDlg('Dialog cleared',mtInformation,[mbOK],0);
end;

procedure TfrmEntry.bmbClearDBClick(Sender: TObject);
var
  i:integer;
begin
  i:=MessageDlg('Are you sure you want to clear the Racers database? (all current data in the database will be lost.)',mtWarning,[mbOK,mbCancel],0);
  if i = mrOk then
  begin
    //clears entire database
    with dmRacers do
    begin

      EmptyTable(tbl1660,'tbl1660');
      EmptyTable(tblXKarts,'tblXKarts');
      EmptyTable(tblTwoPointOne,'tblTwoPointOnes');
      EmptyTable(tblMidB,'tblMidB');
      EmptyTable(tblMidA,'tblMidA');
      EmptyTable(tblLateModel,'tblLateModels');
      EmptyTable(tblSprints,'tblSprints');
      EmptyTable(tblV8,'tblV8');
      EmptyTable(tblHeavyMetals,'tblHeavyMetals');
      EmptyTable(tblHotrods,'tblHotrods');
      EmptyTable(tblPinkrods,'tblPinkrods');
      EmptyTable(tblStockrods,'tblStockrods');
      EmptyTable(tblMinis,'tblMinis');
      EmptyTable(tblDevelopment,'tblDevelopment');

      i:=MessageDlg('Database successfully cleared',mtInformation,[mbOk],0);

      //resets active property of tables
      ResetActiveProp(tbl1660);
      ResetActiveProp(tblXKarts);
      ResetActiveProp(tblTwoPointOne);
      ResetActiveProp(tblMidB);
      ResetActiveProp(tblMidA);
      ResetActiveProp(tblLateModel);
      ResetActiveProp(tblSprints);
      ResetActiveProp(tblV8);
      ResetActiveProp(tblHeavyMetals);
      ResetActiveProp(tblHotrods);
      ResetActiveProp(tblPinkrods);
      ResetActiveProp(tblStockrods);
      ResetActiveProp(tblMinis);
      ResetActiveProp(tblDevelopment);
    end;
  end
  else
  begin
    i:=MessageDlg('Clear aborted',mtInformation,[mbOk],0);
  end;
end;

Example of errors:

Thanks in advance for the help!

Kind Regards

PrimeMinister