[Qt-interest] QSqlQuery and placeholders of the same name

[Anthony Serdyukov]

Thanks for the rapid answer.

So, the rule of thumb is "use unique names for placeholders"?
By the way, I use QODBC driver.

2008/12/30 Bill KING <bill.king at trolltech.com>:
> It was correctly rejected, as in the sqlite case, placeholders are
> handled by the database engine itself and not qt, in this case, sqlite
> has failed to bind correctly, even tho we've told it to. In the case of
> database engines that don't support parameterised queries, then, we do
> substituion ourselves to fill out the query. Honestly, if you're trying
> to "be smart" by re-using the binding, don't, there's too many layers
> that it can go wrong in, and saving one line of code is really not worth
> it in the long run when you factor in testing, debugging, and rewriting
> the code in the end anyway to do both bindings.
>
> Anthony Serdyukov wrote:
>> Good day.
>>
>> Just a simple code.
>>
>> -------------------------------------
>> QSqlQuery query;
>> query.prepare("select * from some_table where columnA = :param AND
>> columnB = :param");
>> query.bindValue(":param", someValue);
>> query.exec();
>> -------------------------------------
>>
>> But it doesn't work. The placeholders of the same name are not bound correctly.
>> First occurrence of :param placeholder gets value of NULL, and the
>> second occurrence gets proper value.
>>
>> I have found a task about it.
>> http://trolltech.com/developer/task-tracker/index_html?method=entry&id=77898
>> The task is rejected without any explanation.
>>
>> Could somebody explain this behavior?
>>
>>
>
>
> --
> Bill King, Software Engineer
> Qt Software, Nokia Pty Ltd
> Brisbane Office
>
>



-- 
Regards,
Anthony