Thanks Andreas - I think we figured it out. It seems that FastReport looks
for the datasets based on just the dataset name, which I never thought of
before because when you set the data sources in the FastReport editor it
shows the form name as well.

So what happened (pretty sure - still need to verify this) was that we had
some forms auto-created (don't know why yet, usually we create the forms on
the fly), and one of the forms had FastReport datasets *with the same name*
as the problematic form! So, FastReport tried to get data from those, and
naturally the queries were empty (they're set at runtime) -> hence the error
message.

Now, what I haven't yet figured out is why it behaves differently when the
report is stored in the DFM. That was what threw me off. Anyway, I'm more
than happy to say it was our own fault :-)

P.S. I'm looking into your FastReport IBO components, and had some trouble
compiling the English resources. Should I email you directly about that, or
do you prefer some other place?


Antti Kurenniemi

----- Original Message -----
From: "Andreas Hesse" <ah@...>
Cc: <ibobjects@yahoogroups.com>
Sent: Friday, February 06, 2009 11:21 AM
Subject: Re: [IBO] Cannot prepare a blank statement -error


> So it is time for debugging.
>
> Halt on this exception and see, what object is causing it and what is
> the stack trace. Compare the object that raise the exception with the
> one that you expect.
>
> Post the information here, so we can help you much better with some more
> informations.
>
> Andreas
>
>
>> Hi all.
>>
>>
>> I have a case which I can't figure out, and it's really hurting me right
>> now. I have an app with about 50 reports, using FastReports. Just a few
>> days
>> ago I noticed that two of my reports are throwing "Cannot prepare a blank
>> statement" error, which seems to come from IBO. As far as I know, I
>> haven't
>> changed anything in those reports in ages, and I checked an older
>> compiled
>> version of the app and it worked just fine.
>>
>> Here's where it gets weird: I set two queries (of TIBOQuery type) at
>> runtime. There's a fairly simple SQL in one of them, and a bit more
>> complex
>> but nothing strange in the second one, just a few joins. If I do
>> something
>> like this after opening the queries:
>>
>> while not HeaderQuery.Eof do
>> begin
>> ShowMessage(HeaderQuery.Fields[0].AsString);
>> HeaderQuery.Next;
>> end;
>>
>> ....it works ok, I can go through all records without any trouble. But,
>> as
>> soon as the report opens, it throws the error mentioned above.
>>
>> Now, the report may be a culprit here, but I'm dumbfounded as to how to
>> start searching for the cause here. The IBO source is way too complex for
>> me
>> to wrap my mind around, so I'm posting this here (as well as in the
>> FastReport newsgroups) in hopes that someone could at least point me
>> towards
>> the solution. Like, in which exact case would that error get thrown
>> usually?
>>
>> Any help greatly appreciated,
>> Antti Kurenniemi
>>
>
>
>
>
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