Zeos/Firebird Exception Handling
lazarus / 16-Databases

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dogriz · 2014-01-25 14:00

Is there a way to handle Firebird Exception message in Lazarus?

ZEOS 7.1.2
Firebird 2.5.2
Lazarus 1.0.xx

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mangakissa · 2014-01-26 14:56

The most datacomponments has the following events.
- OnDeleteError
- OnPosterror
- OnInsertError
 Sometimes (SQBdb has) OnUpdateError

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sin_dragan · 2014-01-27 20:23

Hi i use this with SqlDB, I think you can do the same with Zeos:

Code: [Select]with dmCv.MestaQ do
    begin
      if Izmena then MestoID := Fields[0].AsInteger;
      Close;
      if Izmena then
      begin
        SQL := UpdateSQL;
        Params[2].AsInteger := MestoID;
      end
      else SQL := InsertSQL;
      Params[0].AsString := edtNazivMesta.Text;
      Params[1].AsString := mmKomentarMesta.Text;
      ExecSQL;
      dmCv.FBTran.Commit;
    end;

  except
    on E: EIBDatabaseError do
    begin
      case E.GDSErrorCode of
      335544665 : ShowMessage('Mesto ' + edtNazivMesta.Text + ' već
postoji u bazi.'); //record already exist in DB
      else
        ShowMessage('Greška u radu sa bazom podataka, pozovite IT
službu!');
        Close;
      end;
    end;

//or with Zeos

procedure TForm1.Button1Click(Sender: TObject);
begin
  try
  ZQuery1.ExecSQL;
  ZQuery1.Open;

  except
    on E:EZSQLException do
      ShowMessage('sql error code' + inttostr(e.ErrorCode) +
sLineBreak +e.Message);
  end;
end;

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dogriz · 2014-01-27 21:16

Actually, I want to catch exception message like the one in employee
database.
For example, in employee database there are a few exceptions defined
(CUSTOMER_CHECK, CUSTOMER_ON_HOLD...) and I want to catch exception
message string ("Overdue balance -- can not ship.").
Simple use of try except on E: Exception doesn't give me the message I
want.
And, btw, which version of ZEOS has E:EZSQLException?

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sin_dragan · 2014-01-27 23:21

Try this, it's not a perfect solution but it could serve you.

In ZDbcInterbase6Utils.pas line 814 change to ErrorMessage :=
ErrorMessage + '|' + String(Msg);

Rebuild clean Zeos package.
Add Zstoredproc.

Code: [Select]procedure TForm1.Button1Click(Sender: TObject);
var
  SL: TStringList;
begin
  try
  sl := TStringList.Create;
  ZStoredProc1.StoredProcName := 'SHIP_ORDER';
  ZStoredProc1.Params[0].AsString := 'V93N5822';
  ZStoredProc1.ExecProc;
  except
    on E:EZSQLException do
    begin
      sl.Delimiter := '|';
      sl.StrictDelimiter := true;
      sl.DelimitedText := E.Message;
      ShowMessage(sl[3]);
    end;
  end;
end;

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dogriz · 2014-01-28 09:34

Quote from: sin_dragan on January 28, 2014, 12:21:37 amTry this, it's
not a perfect solution but it could serve you.

In ZDbcInterbase6Utils.pas line 814 change to ErrorMessage :=
ErrorMessage + '|' + String(Msg);

Rebuild clean Zeos package.
Add Zstoredproc.

Code: [Select]procedure TForm1.Button1Click(Sender: TObject);
var
  SL: TStringList;
begin
  try
  sl := TStringList.Create;
  ZStoredProc1.StoredProcName := 'SHIP_ORDER';
  ZStoredProc1.Params[0].AsString := 'V93N5822';
  ZStoredProc1.ExecProc;
  except
    on E:EZSQLException do
    begin
      sl.Delimiter := '|';
      sl.StrictDelimiter := true;
      sl.DelimitedText := E.Message;
      ShowMessage(sl[3]);
    end;
  end;
end;                   


I get this error:
Quoteunit1.pas(45,10) Error: Identifier not found "EZSQLException"
I use ZEOS 7.1.2-stable.

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sin_dragan · 2014-01-29 15:58

I also use 7.1.2-stable, add ZDbcIntfs to use list.

You can try to read the full message from exception, I'll try to find
a way to parse the message without the need to modify zeos source.