If you want to use a primary key that is not an auto_increment field then you need to set the _isPkAutoIncrement flag on the MySql4 object to false. For example, I created a table that uses customer_entity_id as the primary key:

class MyCompany_MyModule_Model_MySql_Subscription
    extends Mage_Core_Model_MySql4_Abstract {
  public function _construct() {
    // Table resource, primary key
    $this->_init('mymodule/mymodule', 'customer_entity_id');
    // The primary key is not an auto_increment field
    $this->_isPkAutoIncrement = false;
  }
}

If the flag is true (the default), then the save() method will always do an update when you provide a value for the primary key and an insert otherwise. That’s just what you want when the primary key is an auto_increment. If the flag is false, then Magento checks for the existence of a row with that primary key value first. If it exists, it does an update and if it doesn’t exist then it does an insert.

1. Login to your Magento admin and enable logging: Configuration | Developer | Log Settings | Enabled = Yes
2. Add Mage::log() statements to your code. For example, in your observer callback: Mage::log(“My special observer called”)
3. Watch the log files. In Linux, the tail command is very helpful for this. From the /var/log folder: tail -f system.log exception.log

Some more tips:

• Include print_r() output in the log like this: Mage::log(“myvar = ” . print_r($myvar, true))
• Add to the exception.log using Mage::logException()
• The Mage class has some useful helper functions (/app/Mage.php)
• Get the actual class name of any object: $name = get_class($object)
• If you copy and paste this code, you’ll probably need to fix the fancy quotation marks.

Scratch

Scratch is a programming language that makes it easy to create your own interactive stories, animations, games, music, and art — and share your creations on the web.

Alice

Alice is an innovative 3D programming environment that makes it easy to create an animation for telling a story, playing an interactive game, or a video to share on the web.

Processing

Processing is an open source programming language and environment for people who want to create images, animations, and interactions.

I couldn’t find a good introductory video for this one. But the documentation and tutorial pages are top notch.

As of April, fewer than 6 out of 10 people use Internet Explorer. The browser trends that we’ve noted over the past several months are continuing with no sign of alteration: IE continues to slip, Firefox and Opera are fairly static, Safari is very slowly moving forward, and Chrome is pushing ahead at breakneck speeds. If we take a closer look at IE, though, we see that version 8 of Microsoft’s browser is actually growing faster than Chrome, but it’s still not enough to counter the overall decaying of IE. –Internet Explorer best at losing, gaining market share

In that article, they point out that the browser share on their site is much different than the average. So I took a look at BigHugeLabs stats to see how it compares:

BigHugeLabs browser market share April vs May 2010

Gruber does a good job of explaining why this is bad (“It’s a bunch of user-hostile SEO bullshit”). I’ll just add that the Javascript from these companies slows down your web browser and then uses your computer to break basic internet functionality (copy/paste and hyperlinks) so that you can be “leveraged.” I hate it when business types say leverage when what they really mean is exploit.

It reminds me a lot of what Snap.com and others like them were/are doing with hyperlinks.

Fortunately, it’s easy to get back control. Modify your hosts file (/etc/hosts on Mac/Linux; uh, someplace else on Windows) and include the following lines:

127.0.0.1 tcr.tynt.com
127.0.0.1 spa.snap.com
127.0.0.1 shots.snap.com

The first line kills Tynt and the next two kill Snap. Their Javascript won’t load, you’ll never even know it was there, and you can carry on using the internet and your computer the way it was intended to be used.

If you are using either of these services on your own blog or website… please stop. It’s obnoxious.

Google Chrome has a similar feature but by default it uses your primary user profile. Here’s what you do to make application shortcuts use an alternate profile:

1. Create your application shortcut
2. Edit it and add –user-data-dir=custom_profile_directory to the launch command

Where custom_profile_directory is a path to where you want the profile saved. Now that application shortcut will have its own cookies, saved passwords, browsing history, the works. You can use this parameter with Chrome when its in browser mode too. Handy if you’re doing web development and you need to be logged into one app as two different people.

My true condition was checking the exit code of a command (e.g. $? -eq 0) but it could be anything. The key is that a temporary file (LOCKFILE) is created for one status and is deleted for the other status. This allows the script to keep track of state between runs. This script only differentiates between two statuses but it wouldn’t be difficult to adapt this to track changes between multiple states (store the current state in LOCKFILE).

Note, the way this is written, the true action will always be executed once after the system is booted.

#!/bin/sh

LOCKFILE=/var/lock/mylockfile
TAG=mytag

if [ some condition is true ]
then
    echo Status 1
    if [ ! -e $LOCKFILE ]
    then
        logger -t $TAG "Message for status 1"
        touch $LOCKFILE
    fi
else
    echo Status 2
    if [ -e $LOCKFILE ]
    then
        logger -t $TAG "Message for status 2"
        rm $LOCKFILE
    fi
fi