Hello Paul,

thanks for your hints.

>Maybe you could try this - it's better practice anyway:

I will follow your procedure, and see what happens:-)

Regards
Rainer

-----Ursprüngliche Nachricht-----
Von: Paul Vinkenoog [mailto:paul@...]
Gesendet: Donnerstag, 15. Mai 2003 16:05
An: IBObjects (E-Mail)
Betreff: Re: [IBO] TIB_Query.FieldByName().AsInterger -> Accessviolation


Hi Rainer,

> I have a Query always doing the same select on the same table.
>
> In a loop :
> <MyQuery>.Refresh;
> with <MyQuery> do
> begin
> First;
> while not EOF do
> begin
> try
> r:=2+FieldByName('DESTINATION').AsInteger;
> except
> ....;
> end;
> ....
>
> I very often end in the exception because of a accessviolation :-(
> What am I doing wrong?

The Access Violation suggests that the fields aren't set up yet,
i.e. the query is unprepared. But the Refresh and the First seem to
work, so...

Maybe you could try this - it's better practice anyway:

{ before the loop, but after making sure the query is prepared: }

FieldDest : TIB_Column = MyQuery.FieldByName( 'DESTINATION' );

{ within the loop: }

r := 2 + FieldDest.AsInteger;

This is more efficient because otherwise the field has to be
found-by-name again and again, for every iteration of the loop.

Then step through your code in the debugger and see at what point it
goes wrong.

I know, this is not exactly the answer to you question but it might
help to hunt down the cause.


Greetings,
Paul Vinkenoog

PS:
Hope I got the Pascal syntax OK - it's been a while :-)



Yahoo! Groups Sponsor

<http://rd.yahoo.com/M=253841.3292458.4586253.1261774/D=egroupweb/S=1705007183:HM/A=1504866/R=1/*http://autos.yahoo.com?refsrc=autos/ads/feature/LREC>
2003 Mini Cooper 2003 Nissan 350Z 2003 BMW M3 2003 Honda Accord 2003 Toyota Camry more...

<http://us.adserver.yahoo.com/l?M=253841.3292458.4586253.1261774/D=egroupmail/S=:HM/A=1504866/rand=558536207>

___________________________________________________________________________
IB Objects - direct, complete, custom connectivity to Firebird or InterBase
without the need for BDE, ODBC or any other layer.
___________________________________________________________________________
http://www.ibobjects.com - your IBO community resource for Tech Info papers,
keyword-searchable FAQ, community code contributions and more !

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> .




[Non-text portions of this message have been removed]