Magento : Define Global, Website, Store, Store View

    Global: This refers to the entire installation.
    Website: Websites are ‘parents’ of stores.  A website consists of one or more stores. Websites can be set up to share customer data, or not to share any data
    Store (or store view group): Stores are ‘children’ of websites.  Products and Categories are managed on the store level.  A root category is configured for each store view group, allowing multiple stores under the same website to have totally different catalog structures.
    Store View: A store needs one or more store views to be browse-able in the front-end.  The catalog structure per store view will always be the same, it simply allows for multiple presentations of the data in the front.  90% of implementations will likely use store views to allow customers to switch between 2 or more languages.

Magento : get file paths and URLs

Get URL paths of your magento folder structure – Absolute URL Path

Mage::getBaseUrl() => Gets base url path e.g. http://my.website.com/

Mage::getBaseUrl(‘media’) => Gets MEDIA folder path e.g. http://my.website.com/media/

Mage::getBaseUrl(‘js’) => Gets JS folder path e.g. http://my.website.com/js/

Mage::getBaseUrl(‘skin’) => Gets SKIN folder path e.g. http://my.website.com/skin/

Get DIRECTORY paths (physical location of your folders on the server) – Relative URL Path

Mage::getBaseDir() => Gives you your Magento installation folder / root folder e.g. /home/kalpesh/workspace/magento

Mage::getBaseDir(‘app’) => Gives you your Magento’s APP directory file location e.g. /home/kalpesh/workspace/magento/app

Mage::getBaseDir(‘design’) => Gives you your Magento’s DESIGN directory file location e.g. /home/kalpesh/workspace/magento/design

Mage::getBaseDir(‘media’) => Gives MEDIA directory file path

Mage::getBaseDir(‘code’) => Gives CODE directory file path

Mage::getBaseDir(‘lib’) => Gives LIB directory file path

Get Current URL – whole URL path

Mage::helper(‘core/url’)->getCurrentUrl()

Also we can use as

base Mage::getBaseDir()
Mage::getBaseDir(‘base’) /var/www/magento/
app Mage::getBaseDir(‘app’) /var/www/magento/app/
code Mage::getBaseDir(‘code’) /var/www/magento/app/code
design Mage::getBaseDir(‘design’) /var/www/magento/app/design/
etc Mage::getBaseDir(‘etc’) /var/www/magento/app/etc
lib Mage::getBaseDir(‘lib’) /var/www/magento/lib
locale Mage::getBaseDir(‘locale’) /var/www/magento/app/locale
media Mage::getBaseDir(‘media’) /var/www/magento/media/
skin Mage::getBaseDir(‘skin’) /var/www/magento/skin/
var Mage::getBaseDir(‘var’) /var/www/magento/var/
tmp Mage::getBaseDir(‘tmp’) /var/www/magento/var/tmp
cache Mage::getBaseDir(‘cache’) /var/www/magento/var/cache
log Mage::getBaseDir(‘log’) /var/www/magento/var/log
session Mage::getBaseDir(‘session’) /var/www/magento/var/session
upload Mage::getBaseDir(‘upload’) /var/www/magento/media/upload
export Mage::getBaseDir(‘export’) /var/www/magento/var/export

Magento : add thumnail in admin grid

Remember that grid is working fine.Here module is consider as Bd_Collegeprogram

First add the code in the _prepareColumns() function
$this->addColumn("image", array(
                "header" => Mage::helper("collegeprogram")->__("Image"),
                "index" => "image",
                'type' => 'image',
                'width' => '50px',
                'renderer'  => 'collegeprogram/adminhtml_collegeprogram_renderer_image'
                ));
Now create a block as adminhtml_collegeprogram_renderer_image
class Bd_Collegeprogram_Block_Adminhtml_collegeprogram_Renderer_Image extends Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Abstract{

    public function render(Varien_Object $row)
    {
        $html = '<img ';
        $html .= 'id="' . $this->getColumn()->getId() . '" ';
        $html .= 'src="' . $row->getData($this->getColumn()->getIndex()) . '"';
        $html .= 'class="grid-image ' . $this->getColumn()->getInlineCss() . '"/>';
        return $html;
    }
}