Formatting A Price For The Current Locale

Declare an admin layout XML file for your module in your config.xml:

<config>
    <adminhtml>
        <layout>
            <updates>
                <your_module>
                    <file>your-module.xml</file>
    ...

Adding A Tab To The Product Screen

1. Declare an admin layout XML file for your module in your config.xml:

   ...

Using the database to inspect EAV-based entity types can be a real pain in the ass, so here are a bunch of queries that let you inspect some popular EAV entity types easily. This practice can be applied to any EAV entity type, however as there are...

To add a class via layout XML:

<reference name="root">
    <action method="addBodyClass"><classname>whatever</classname></action>
</reference>

Or to add via code, from a controller or block

if ($root = $this->getLayout()->getBlo...

Mage::registry('current_category');

Mage::registry('current_product');

Potentially confusing due to the 3 methods you could use, all of which are in Mage_Catalog_Model_Product:

public function getUrlPath($category=null)
public function getUrlInStore($params = array())
public function getProductUrl($use...

For when you have no local.xml:

<?xml version="1.0"?>
<!--
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Academic Free License (AFL 3.0)
 * that is bundled with this package in...

Magento has a Datetime backend model but formats a Zend_Date object without the time. So if you want to store datetime (actually with time) you will need to setup your own backend model.

Here is how i've done it:

class Namespace_Module_Mod...

Often, you'll want to add a column to a collection used in a grid, and to do so you'd use _prepareCollection():

protected function _prepareCollection()
{
    $collection = Mage::getResourceModel($this->_getCollectionClass());
  ...