TCSVDataset FieldDefs defaults to ftString, 255 when reading from CSV-
file
lazarus / 16-Databases

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Vodnik · 2023-03-02 09:17

I can't succeed defining  CSVDataset1.FieldDefs in case when dataset
is linked to existing CSV-file.
When dataset is opened, FieldDefs are overwritten with
DataType=ftString and Size=255.
Is it a bug, an idea or I'm doing something wrong?
Test project  attached.
First run - no CSV file - FieldDefs are OK - CSV file is created
accordingly.
Second run - CSV file exist - FieldDefs are default - record appended
to CSV in wrong format.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
TestCSVDS; uses csvdataset, sysutils, db; var  CSVDataSet1:
TCSVDataSet;     CSVFileName: String = 'data.csv';     I:
Integer; begin  CSVDataset1:=TCSVDataset.Create(nil);  try   
CSVFileName:=ExtractFilePath(Paramstr(0)) + CSVFileName;   
CSVDataset1.FileName:=CSVFileName;   
CSVDataset1.CSVOptions.FirstLineAsFieldNames:=False;   
CSVDataset1.FieldDefs.Add('Date and time', ftDateTime);   
CSVDataset1.FieldDefs.Add('Duration', ftTime);   
CSVDataset1.FieldDefs.Add('Event', ftString,40);     if
FileExists(CSVFileName) then begin       Writeln('File '+CSVFileName+'
exist');     end else begin       CSVDataset1.CreateDataset;     
 Writeln('File '+CSVFileName+' not exist');     end;   
CSVDataset1.Open;    CSVDataset1.AppendRecord([EncodeDate(2023,03,03),
EncodeTime(13,08,01,000),'Oleg']);    for I:= 0 to
csvdataset1.FieldDefs.Count-1 do begin      Writeln('Record: ',I,',
data type: ',csvdataset1.FieldDefs.Items[I].DataType,', data size: ',
csvdataset1.FieldDefs.Items[I].Size);    end;    CSVDataset1.Close;  
CSVDataset1.Free;    Readln;  except   end;end. 
File data.csv after 2 runs:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
03.03.2023,13:08:01,Oleg44988,"0,547233796296296",Oleg

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tatamata · 2023-03-02 11:07

Thank you for asking this question, I have noticed and wondering about
the same thing while working on new ZMSQL version. Curious to see
answers.