The Magento class inheritance list below represents classes that are used when extending Magento functionality. This includes when defining new classes and the parent classes that they should extend from.
Blocks
Mage_Core_Block_Template class.Mage_Core_Block_Template class in turn extends the Mage_Core_Block_Abstract class.Mage_Core_Block_Abstract also extends the Varien_Object class.Helpers
Mage_Core_Helper_Abstract class.Models
Mage_Core_Model_Abstract.Mage_Core_Model_Abstract extends Varien_Object.Resource Models
Mage_Core_Model_Resource_Db_Abstract.EAV Resource Models
Mage_Eav_Model_Entity_Abstract.Collections
Mage_Core_Model_Resource_Db_Collection_Abstract.EAV Collections
Mage_Eav_Model_Entity_Collection_Abstract.Controllers
Mage_Core_Controller_Front_Action.Mage_Adminhtml_Controller_Action.Mage_Core_Controller_Front_Action and Mage_Adminhtml_Controller_Action extend Mage_Core_Controller_Varien_Action.Adminhtml Grids
Mage_Adminhtml_Block_Widget_Grid_Container.Mage_Adminhtml_Block_Widget_Grid.Adminhtml Forms
Mage_Adminhtml_Block_Widget_Form_ContainerMage_Adminhtml_Block_Widget_Form.Setup Scripts
Mage_Core_Model_Resource_Setup, although this class is referenced in config.xml within a pair of class nodes within the pair of resources nodes.Mage_Eav_Model_Entity_Setup class.Mage_Catalog_Model_Resource_Setup class.Mage_Customer_Model_Resource_Setup class.Product Types
Mage_Catalog_Model_Product_Type_Abstract.Totals
Mage_Sales_Model_Quote_Address_Total_Abstract.Shipping
Mage_Shipping_Model_Carrier_Abstract and implement Mage_Shipping_Model_Carrier_Interface.Payment
Mage_Payment_Model_Method_Abstract.Note: This article is based on Magento Community/Open Source version 1.9.