tDBF index by date?
lazarus / 16-Databases

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bill0287 · 2014-01-12 00:25

I am having trouble setting a date index for an already existing dbf
table (that doesn't have any defined indexes).

I looked at what's on the tdbf wiki page but I can't find the right
sequence to create and apply the index. I have tried this:

Code: [Select]procedure TSalesContractForm.FormCreate(Sender:
TObject);
begin
  SalesDBf.Active := False;
  SalesDBf.FilePath := MainForm.DatabasePath;
  SalesDBf.Active := True;
    SalesDBf.Exclusive:=True;
    SalesDbf.AddIndex('IDXDATE', 'DTOS(DATE)', []);
    SalesDBf.Exclusive:=False;
    SalesDBf.IndexName := 'IDXDATE';
    SalesDBf.First;
end;
but I get an error about exclusive access...is what I am trying to do
even allowed with dbf tables?

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BigChimp · 2014-01-12 09:14

Ok, so you did put in the
Code: [Select]SalesDBf.Exclusive:=True;
... trouble is, it's too late, as it's after
Code: [Select]SalesDBf.Active := True; //equivalent to SalesDBF.Open;

Also, you try to switch back exclusive to false afterwards. I suspect
this won't work and you'll have to close, set exclusive to false &
reopen... but haven't checked.

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bill0287 · 2014-01-12 18:53

This seems to work okay:

Code: [Select]procedure TForm1.CreateIndexButtonClick(Sender:
TObject);
begin
  with DBf1 do begin
    Close;
    TableName := Edit1.Caption; //setting dbf table name
    FilePath := ExtractFilePath(paramstr(0)); //setting dbf filepath
    Exclusive:=True;
    Open;
    AddIndex('IDXDATE', 'DTOS(DATE)', []);
    Exclusive:=False;
    IndexName := 'IDXDATE'; //setting dbf indexname
    First; //start at first record
  end;
end;