 | | | -none- | -none- 2007-09-04 - By Warren Young
Back
Yassin wrote:
>> In MySQL++ v2.3, the Result object must outlive the Row objects that
>> come from it, but with storein(), the Result object only lasts as long
>> as the storein() call.
>
> Can you explain me why?
MySQL++ is open source, and its code is pretty easy to read these days.
Hint, hint.
If you had looked for references to Result in lib/row.cpp, you would
have found that there are several places where calling a method on a Row
delegates part of the function back to the Result object that created
it. This was done for efficiency and simplicity: why make each Row
carry extra copies of data its parent Result holds when it can just keep
a pointer back to its parent and ask it when it needs the info?
The new Row code in v3.0 gets around this without a huge speed and space
penalty by using a much more complex memory management scheme. (See
recent posts to the list about reference counted smart pointers.) If I
were the original authors of MySQL++, I wouldn't have wanted to make the
memory management complex at such an early stage of development, either.
It's only a sign of the increasing maturity of MySQL++ that we can do
such things.
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