Magento code cheatsheet

This is blatantly stolen from sycha.com for my reference…

Magento Database Models

The best way to access and manipulate data in Magento is by using the provided objects and their associated functionality.. For example, you can get a Magento category model like this:

$model_category = Mage::getModel('catalog/category');

With your category model you now retrieve data e.g. get all child categories of category ID 2 and echo the name

$model_category = Mage::getModel('catalog/category');
foreach ($model_category->getCategories($id=2) as $category) {
        echo $category->getName();
}

Refer to the API documentation to see what methods are available.

Magento Helper Classes

Magento has helper classes which are pretty handy also. For example, you can get a Magento category helper like this:

$helper = Mage::helper('catalog/category');

Your helper will have a bunch of methods defined for performing common tasks. For example, you can get all your stores top level categories as follows:

$helper = Mage::helper('catalog/category');
foreach ($helper->getStoreCategories() as $category) {
        echo $category->getName();
}

Check this file to see what methods are available in the catalog category helper: magento/app/code/core/Mage/Catalog/Helper/Category.php

References: Magento Database Models, Helpers and Raw SQL Queries