Run it in a debugger and tell us on which line it crashes?
And you're using the mysql4 unit. You know what the consequences are?
What's the version of you're mysql-client?
(And ask yourself: do I really want to use mysql?)
On Tue, 2006-09-19 at 10:13 +0200, A.J. Venter wrote:
> Mmm,
> So does nobody know what I'm doing wrong ? Or is it not a problem in my code
> ?
> Any idea what I should check ?
>
> A.J.
> On Monday 18 September 2006 15:17, A.J. Venter wrote:
> > I have just started on a new project, which is mysql backed - beginning
> > with a fairly abstract unit which a large number of different lazarus
> > programs will use to communicate with the DB.
> >
> > But I ran into a very strange problem quite early on, I can connect to the
> > DB without hassles, but as soon as I try to do a query - I get a crash, and
> > I have no idea why... :S
> >
> > My current test calls look like this:
> >
> > ZC_DBConnect;
> > ZC_Settings : TZC_Settings.Create;
> > Writeln(ZC_Settings.GetPricePerUnit);
> >
> > TraceBack says it's crashing on line 96:
> > if (mysql_query(socket,pchar(Query)) < 0) then
> >
> >
> > The unit in full goes:
> > unit libzybacafe;
> >
> > {$mode objfpc}{$H+}
> >
> > interface
> >
> > uses
> > Classes, SysUtils,dialogs,mysql4;
> >
> > procedure ZC_DBConnect;
> > Function ZC_DBQuery(Query:String):PMYSQL_RES;
> >
> > type
> > TZC_Settings = class
> > private
> > {Private Declarations}
> > FCurrencySymbol : String;
> > FUnitLength : Integer;
> > FPricePerUnit : Real;
> > FResult : PMySQL_RES;
> > FRow: MYSQL_ROW;
> > Procedure LoadFromDB;
> > Procedure SaveToDB;
> > public
> > { public declarations }
> > Function GetCurrencySymbol : String;
> > Function GetUnitLength : Integer;
> > Function GetPricePerUnit: Real;
> > Procedure SetCurrencySymbol(NewSymbol:String);
> > Procedure SetUnitLength(NewLength:Integer);
> > Procedure SetPricePerUnit(NewPrice : Real);
> > end;
> >
> > Var
> > Socket : PMysQL;
> >
> > implementation
> >
> > procedure ZC_DBConnect;
> > Var
> > DBCFG : TSTringList;
> > I : Integer;
> > H,U,P,D : String;
> > qmysql : TMYSQL;
> > alloc : PMYSQL;
> >
> > Begin
> > DBCFG := TSTringList.Create;
> > Try
> > {$IFDEF Unix}
> > DBCFG.LoadFromFile('/etc/zybacafe.cfg');
> > {$ENDIF}
> > {$IFDEF Win32}
> > DBCFG.LoadFromFile('C:\Program Files\ZybaCafe\zybacafe.cfg');
> > {$ENDIF}
> > except
> > ShowMessage ('Error Loading database configuration !');
> > Halt;
> > end;
> > For I := 0 to DBCFG.Count -1 do
> > begin
> > If pos('HOST=',uppercase(DBCFG[I])) <> 0 then
> > begin
> > H := DBCFG[I];
> > Delete(H,1,pos('=',H));
> > end;
> > If pos('USERNAME=',uppercase(DBCFG[I])) <> 0 then
> > begin
> > U := DBCFG[I];
> > Delete(U,1,pos('=',U));
> > end;
> > If pos('PASSWORD=',uppercase(DBCFG[I])) <> 0 then
> > begin
> > P := DBCFG[I];
> > Delete(P,1,pos('=',P));
> > end;
> > If pos('DATABASE=',uppercase(DBCFG[I])) <> 0 then
> > begin
> > D := DBCFG[I];
> > Delete(D,1,pos('=',D));
> > end;
> >
> > end;
> > alloc := mysql_init(PMYSQL(@qmysql));
> > socket := mysql_real_connect(alloc, pchar(h), pchar(u),
> > pchar(p),pchar(d), 0, nil, 0);
> > if socket=Nil then
> > begin
> > ShowMessage('Error connecting to
> > database:'+LineEnding+StrPas(mysql_error(@qmysql)));
> > halt;
> > end;
> > end;
> >
> > Function ZC_DBQuery(Query:String):PMYSQL_RES;
> > Var RecBuf : PMYSQL_RES;
> > Begin
> > if (mysql_query(socket,pchar(Query)) < 0) then
> > begin
> > ShowMessage('Query failed '+ StrPas(mysql_error(socket)));
> > end
> > else
> > begin
> > recbuf := mysql_store_result(socket);
> > if RecBuf=Nil then
> > begin
> > ShowMessage('Query returned nil result.');
> > end else
> > ZC_DBQuery := RecBuf;
> > end;
> > end;
> >
> > Procedure TZC_Settings.LoadFromDB;
> > Var Result : PMYSQL_RES;
> > Q : String;
> > Begin
> > FResult := ZC_DBQuery('SELECT * FROM settings;');
> > FRow := Mysql_Fetch_Row(FResult);
> > If FRow = Nil then
> > begin
> > showMessage('You have no stored site-settings.'+LineEnding+'Setting
> > all to defaults');
> > FCurrencySymbol := '$';
> > FUnitLength := 1;
> > FPricePerUnit := 1.0;
> > Q := 'INSERT INTO settings VALUES("","'+FCurrencySymbol;
> > Q :=
> > Q+'","'+IntToStr(FUnitLength)+'","'+FloatToStr(FPricePerUnit)+'");';
> > Result := ZC_DBQuery(Q);
> > end else
> > begin
> > FCurrencySymbol := FRow[1];
> > FUnitLength := StrToInt(FRow[2]);
> > FPricePerUnit := StrToFloat(FRow[3]);
> > end;
> >
> > end;
> >
> > Procedure TZC_Settings.SaveToDB;
> > Var
> > Query : String;
> > Begin
> > Query := 'UPDATE TABLE settings SET currencysymbol="'+FCurrencySymbol;
> > Query := Query+'",unitlength="'+IntToStr(FUnitLength);
> > Query := Query+'",priceperunit="'+FloatToStr(FPricePerUnit)+';';
> > FResult := ZC_DBQuery(Query);
> > end;
> >
> > Function TZC_Settings.GetCurrencySymbol : String;
> > Begin
> > LoadFromDB;
> > GetCurrencySymbol := FCurrencySymbol;
> > end;
> >
> > Function TZC_Settings.GetUnitLength : Integer;
> > Begin
> > LoadFromDB;
> > GetUnitLength := FUnitLength;
> > end;
> >
> > Function TZC_Settings.GetPricePerUnit: Real;
> > Begin
> > LoadFromDB;
> > GetPricePerUnit := FPricePerUnit;
> > end;
> >
> > Procedure TZC_Settings.SetCurrencySymbol(NewSymbol:String);
> > Begin
> > FCurrencySymbol := NewSymbol;
> > SaveToDB;
> > end;
> >
> > Procedure TZC_Settings.SetUnitLength(NewLength:Integer);
> > Begin
> > FUnitLength := NewLength;
> > SaveToDB;
> > end;
> >
> > Procedure TZC_Settings.SetPricePerUnit(NewPrice : Real);
> > Begin
> > FPricePerUnit := NewPrice;
> > SaveToDB;
> > end;
> >
> > initialization
> >
> >
> > end.
>
--
Met vriendelijke groeten,
Joost van der Sluis
CNOC Informatiesystemen en Netwerken
http://www.cnoc.nl
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