From: David Masover <ninja@...>
Date: 2010-01-17T04:26:31+09:00
Subject: Re: How can I modify the xml file directly?

On Saturday 16 January 2010 11:50:04 am Seebs wrote:
> On 2010-01-16, Milo Luo <lxybhbh@gmail.com> wrote:
> > I meant without string or tmp file, write to original file.
> 
> In general, on most systems, the only modifications you can make without
> a temporary file or something comparable are those which do not change the
> number of characters in a file.  You can't insert or delete characters in
> the middle of a file.

Not true; you can append to the end of a file.

But yes, that's the point, and that's why XML (or JSON, or Yaml) is not 
efficient as a database format, unless you work around it somehow. It's fine 
(preferred, even) if the files are small enough, but yes, you are going to 
have to write to a tempfile first, then move that on top of the original file.

Or, if you're feeling reckless, you can truncate the original file to 0, then 
overwrite it directly.