It seems there are two camps when it comes to SQL and how to do database optimizations - the “generic camp” and “the specialist camp”. While I don’t consider myself an extremist, I am absolutely in the specialist camp and this little post is an explanation of why.

SQL is a generic database langauge . There are a few different standards in use (the language has progressed over time), but the core of the SQL language is pretty much the standard in most databases. It’s probably also standard - in any database - that the SQL standard has been extended with database-specific extensions which provides optimizations, functions or other options not available in the SQL standard.

I just discovered O’Reilly CodeZoo today. What a cool idea – ”Find good code, use it quickly”. The net is just littered with bad code samples and finding a place where a high quality standard is set might be a great idea. Only problem is that the (probably) two most used languages on the net - PHP and Perl - aren’t allowed in (so far). Too bad, while good Perl code can be found, it’s hardly impossible to find any quality PHP code samples anywhere.

With Perl you can do many interesting transformations of IP-numbers. Below is two small examples allowing conversions from “IP quad” (xxx.xxx.xxx.xxx) format to a single decimal and back. The decimal format may be more convenient and efficient to store in a database.

  sub ip2dec ($) {
    return unpack N => pack CCCC => split /\\./ => shift;
  }

  sub dec2ip ($) {
    return join '.' => map { ($\_\[0\] >> 8\*(3-$\_)) % 256 } 0 .. 3;
  }

In CPAN you can find many modules aimed at using and manipulating IP-addressees.

I’ve been moving a fairly large part of my private mail to my Gmail account.  Gmail do have some amazing features for searching, labeling and handling mail and the virtually unlimited storage is also pretty cool - Much cooler than keeping a huge mail-archive on an IMAP-server or having it on a local fragile hard disk.

One of the more recent things I’ve started using GMail for is backups of this site. With the wp-db-backup plugin for Wordpress a backup of the entired database is mail to my gmail account every 24 hours and using filters I’m applying a ”backup”-label and auto-archiving it (and avoiding noise in inbox).

To every modern web 2.0 site offering tagging seems to be an absolute requirement. While I may agree, that tagging in some cases may offer some improvements in content navigation over many other points, I do think it’s been too abused in way to may cases.

Tags on sites such as Flickr and Del.icio.us are absolutely fantastic. They offer some cross navigation options, which would probably be near impossible, if not for the tags. I often find my self exploring links though del.icio.us, since the content stored there generally seem to be of a muh high quality than a simple Google search on a common term.

The past days I’ve been posting stories with a few code samples – Perl, PHP, Javasscript and/or HTML. While Wordpress is fantastic to a number of things, handling sourcecode examples in the posts, reallly isn’t one of them.

I’ve been playing with a number of plugins, but none of them really works for me. What I’m looking for is this:

• It must be able to handle HTML, Javasscript, PHP and Perl sourcecode.
• The code samples should work with the visual editor (preferably entered in this, but ”code mode” is quite alright) – Visual post editing shouldn’t break the code example.
• The plugin should be alive (maintained and tested with recent wordpress releases).

I would have thought it would have been easy to find a plugin that covered the above requirements, but so far I’ve had very little luck – any suggestions?

Sometimes you might need to change the address a form submits to, it’s quite easy with javascript. One example could be if you - like me - from time to time is hit hard by comment-spammers. Changing the submit URL on the form with javascript, makes it at least somewhat harder for “automated brainless robots” to kill your site in a spam attack.

The recipie below is a very simple example, but so far it seems to work quite well:

<script type="text/javascript">
function doSubmit() {
  var target1 = 'hello';
  var target2 = 'world';
  var target3 = '.cgi';

  var supertarget = target0 + target1 + target2 + target3;
  var theForm=document.getElementById("theForm");
  theForm.action = supertarget;
  theForm.submit();
}
</script>

<form id="myForm" method="post" action="some\_fake\_address.php">
<input type="text" name="dummy field" value="">
<input type="button" onclick="javascript:doSubmit();">
</form>

Suppose you’ve just filled you digital camera with an endless stream of photos. You want to place them online at your website, but placing 5+ megapixel files online, well…probably a bad idea. Let’s resize them to a propper size - and why not use Perl and ImageMagick for the job.  Not a problem, here’s a complete example on how to resize all images in a directory . Make sure you have ImageMagick installed.

I’m sure most people only thing of PHP as a Weblanguage due to be called through a browser. It has however since version 4.3.0 also been possible to use PHP on the commandline - as you do with Perl, Shell scripts and likewise. If you’re using Linux (or an other Unix-like operating system - including Mac OSX) you probably have a few small programs available which can make it a breeze to check if the syntax in all you PHP scripts is correct.

Changing files from one format to another is quite easy with a little bit of ImageMagick . In the example below a JPG image (test.jpg) is converted into a GIF-image (test.gif). To output in a different (ImageMagick supported ) format, just change the “image->Set” line.

#!/usr/bin/perl -w use strict; use Image::Magick;
my $image = Image::Magick->new();

# To explicitly set image format use this instead: 
# my $image = Image::Magick->new(magick=> 'JPEG');
my $x = $image->Read('test.jpg'); 
$x = $image->Set(magick => 'GIF'); $x = $image->Write('test.gif');
exit();