$connection = Mage::getSingleton('core/resource')->getConnection('default_setup');

Then we will use this connection to instanciate Zend_Db_Select object and write query like

$select = new Zend_Db_Select($connection);
$table = 'catalog_product_index_price';
$select->from($table, array('entity_id'))
	->where('entity_id = ?', $entityId);

// Getting result

$result = $select->query();
$rowCount = $result->rowCount();

if ($rowCount) {
	foreach ($result->fetchAll() as $data) {
		return $data['entity_id'];
	}
}

The above one is for select but what about inserting data? It is simple as well. All you have to do is create an associative array of data to be inserted and use connection to add data. For example

$connection = Mage::getSingleton('core/resource')->getConnection('default_setup');
$table = 'catalog_product_index_price';

$insertData = array();
$insertData ['price'] = $productPrice;
$insertData ['final_price'] = $productPrice;
$insertData ['min_price'] = $productPrice;
$insertData ['max_price'] = $productPrice;
$insertData ['tier_price'] = $productPrice;

$connection->insert($table, $insertData);

I think this should be a good enough code for using custom query in Magento. About Zend_Db_Select please visit http://framework.zend.com/manual/en/zend.db.select.html.

[UPDATE]

If you want to update the data with custom query and have a condition then you can send the conditions as array as third params to update function. For example.

$connection = Mage::getSingleton('core/resource')->getConnection('default_setup');
$table = 'catalog_product_index_price';

$updateCond = array(); // Update condition array container.
$insertData = array();
$insertData ['price'] = $productPrice;
$insertData ['final_price'] = $productPrice;
$insertData ['min_price'] = $productPrice;
$insertData ['max_price'] = $productPrice;
$insertData ['tier_price'] = $productPrice;

$updateCond [] = 'store_id = 0';
$updateCond [] = 'entity_id = 3';

$connection->insert($table, $insertData, $updateCond);

Happy Brogramming!!

Next place to look into will be .. Yes! the model eav/entity_increment_numeric. And if you see the model class Mage_Eav_Model_Entity_Increment_Numeric there is only one Method in this class the public function getNextId() which is responsible to the the Next increment ID, needless to say its parent has other methods as well since you might have already understood. So if some how you can trigger the right Increment Model for any entity type and the call this method, you must get the next increment ID of order/invoice/shippment.

That was the “prose” part now lets get down to the “code poetry”. Here’s how you first find the appropriate increment ID and then fetch the new Increment ID.

            //Get the Entity Type Increment Model you want, our case invoice
            // @var $entity_type_model Mage_Eav_Model_Entity_Type
            $entity_type_model=Mage::getSingleton('eav/config')->getEntityType('invoice');

            //Triggering the getNextId() of the Increment Model
            //@var $invoiceNew Mage_Sales_Model_Order_Invoice
            $new_incr_id = $entity_type_model->fetchNewIncrementId($invoiceNew->getOrder()->getStoreId());

Now, you have the generated Invoice Increment ID. This can be helpful in cases when you want to do something else before Invoice is created but you want to now the Increment Id before hand. Hope this helps.

The two conditions are:

1. If an element of the form already has a value, disable that form element.
2. On triggering an event by acting on some form element to change other form’s element’s attribute value.

If an element of the form already has a value, disable that form element

Lets take an example of core’s customer creation Admin form. What we can see while creating a customer from Admin end, the field “Associate to Website” is available to change for the first time. But when you are editing a customer info the very field is disabled. Lets see how this can be acheivable. If you look into Mage_Adminhtml_Block_Customer_Edit_Tab_Account class you can see the following chunk of code.

  if ($customer->getId()) {
            $form->getElement('website_id')->setDisabled('disabled');
            $form->getElement('created_in')->setDisabled('disabled');
        }

What this does is checks for the Id of the customer if it is present the form elements disabled attribute is set to disabled. So initially while creating a new customer this condition is not fulfilled while on edition of the customer data the condition is fulfilled and hence the form element website_id and the created_in are disabled. This was just an example, you can also write similar conditions for your custom form. Suppose your data for the current form is in $formData variable and then by checking certain field value you can add similar condition.

$formData=Mage::registry('current_custom_data');

if(!empty($formData->getMyField())){
	$targetElement=$form->getElement("my_field");

	//For Disabling the field (Value will not be posted on form submit)
	$targetElement->setDisabled('disabled');

	//Or for making the field readonly
	$targetElement->setReadonly(true);

}

On triggering an event by acting on some form element to change other form’s element’s attribute value

Lets take the same customer edition page, you can see a checkbox with label Send auto-generated password. If you check that checkbox then the New Password textfield above it gets disabled. To get the similar interactivity for custom form you will have to do as following.

$eventElem=$fieldset->addField('nocode', 'checkbox', array(
                'label' => Mage::helper('customer')->__('Event Element'),
                'name'  => 'eventelem',
                'id'    => 'eventelem',
				'value'=>1,
				'onclick'=>'modifyTargetElement(this)',
            ));

		$eventElem->setAfterElementHtml('<script>
			function modifyTargetElement(checkboxElem){
				if(checkboxElem.checked){
					$("target_element").disabled=true;
				}
				else{
					$("target_element").disabled=false;
				}
			}
		</script>');

What you can see is after an element of a form is initiallized you can add HTML codes (which of course for us is only Javascript code) by calling a setAfterElementHtml method and write the implementation of the function called on the event of the Event element.
I’ve tried to be more explanatory as possible, if you still have any confusion there is always a comment box below. Happy Coding!

I will try to describe this issue by taking a case of changing the Magento’s login functionality to a Ajax powered login functionality. So after this you will be able to implement a login function in a pop-up div in any page, unlike the default Magento’s seperate login page. I will leave the pop-up div part to you and get started with the real business (AJAX and JSON).

Presuming that you will use Mini-Login form. Here is how you proceed.

1. Change Submit type button to Button type button.
2. Register OnClick Javascript event of that button and its Handler
3. In the Handler function call Ajax Request for login
4. Show Error Message or redirect to customer Dashboard

Your mini.login.phtml should be like this

<form action="<?php //echo $this->getPostActionUrl() ?>" id="mini-login-form" method="post">
    <fieldset>
        <p><label><?php echo $this->__('Email') ?>:</label> <input name="login[username]" class="input-text" /></p>
        <p><label><?php echo $this->__('Password') ?>:</label> <input name="login[password]" class="input-text" /></p>
        <p><input type="button" onClick="handlerFunction()" value="<?php echo $this->__('Login') ?>" /></p>
    </fieldset>
</form>

<script type="text/javascript">
<!--
function handlerFunction(){

// Write These codes only after form Validation

// Making Ajax Request
		var request = new Ajax.Request(
			//Defining Ajax Request URL, We are calling custom Controller Ns_Mylogin_AccountController Class (Defined Below)
        	'<?php echo $this->getUrl("mylogin/account/loginPost") ?>',
           	{
            	method: 'post',
                onComplete: function(transport){ // Defining Complete Callback Function

                	// Getting Ajax Response Text Which is JSON Object
                	var jsonResponse=transport.responseText;
                	//Checking JSON Objects property and performing related action
                	// You will understand the response Text format after going through the controller description (Below)
                	if(jsonResponse.error){
                		alert("Error Occured");
						return false;
                	}
                	else{
                		window.location.href=jsonResponse.url;
                	}
                },
                parameters: Form.serialize($("mini-login-form"))	// Seriallizing the form input values
        	}
        );
}
//-->
</script>

Please see inline comments for better understanding. Now our next set should be setting up our custom controller. I’ll not get into details of setting up modules and all but directly to our controller class Ns_Mylogin_AccountController. What I’ve done is just taken the core’s loginPostAction function of Mage_Customer_AccountController and added some codes there. Please see there is a comment on each line added apart from the default Magento’s core code.

<?php
require_once("Mage/Customer/controllers/AccountController.php");
class Ns_Mylogin_AccountController extends Mage_Customer_AccountController{
	/**
	 * Login post action
	 * @return JSON Object
	 */
	public function loginPostAction()
	{
		// Added Line #1
		$result["error"]=0;

		$session = $this->_getSession();

		if ($this->getRequest()->isPost()) {
			$login = $this->getRequest()->getPost('login');
			if (!empty($login['username']) &amp;&amp; !empty($login['password'])) {
				try {
					$session->login($login['username'], $login['password']);
					if ($session->getCustomer()->getIsJustConfirmed()) {
						$this->_welcomeCustomer($session->getCustomer(), true);
					}
				} catch (Mage_Core_Exception $e) {
					switch ($e->getCode()) {
						case Mage_Customer_Model_Customer::EXCEPTION_EMAIL_NOT_CONFIRMED:
							//Added Line #2
							$result["error"]=1;
							$message = Mage::helper('customer')->__('This account is not confirmed. <a href="%s">Click here</a> to resend confirmation email.', 						Mage::helper('customer')->getEmailConfirmationUrl($login['username']));
							break;
						case Mage_Customer_Model_Customer::EXCEPTION_INVALID_EMAIL_OR_PASSWORD:
							//Added Line #3
							$result["error"]=1;
							$message = $e->getMessage();
							break;
						default:
							//Added Line #4
							$result["error"]=1;
							$message = $e->getMessage();
					}
					$session->addError($message);
					$session->setUsername($login['username']);
				} catch (Exception $e) {
					// Mage::logException($e); // PA DSS violation: this exception log can disclose customer password
				}
			} else {
				//Added Line #5
				$result["error"]=1;
				$session->addError($this->__('Login and password are required'));
				//Added Line #6
				$this->getResponse()->setBody(Mage::helper('core')->jsonEncode($result));
			}
		}
		//Added Line #7
		$result["url"]=$this->_loginPostRedirect();
		//Added Line #8
		$this->getResponse()->setBody(Mage::helper('core')->jsonEncode($result));
	}

What I’ve done is added an array $result that will hold value if there is error or not while processing the user’s request. If there is error that array will hold $result['error']=1 else it will be as initiallized in Added Line #1. From Added Line #2 through Added Line #5, we have various condition to check for error and set our $result variable.

On Added Line #7 we have called another function (which we we rewrite as well) that will give us the url location identifying which location should be redirect after successful login. The implementation of function is given below. Finally in Added Line #8 and Line #6 we have encoded our $result array into JSON format and send as the response.

For visuallization our $result array will be one of the following.

1. Case (No Error) : $result["error"]=0; $result["url"]=”SOME Redirect URL”
2. Case (Error) : $result["error"]=1;

This JSON encoded response will be then used by the ajax call back function defined and perform related action.

Here’s the _loginPostRedirect() function which I mentioned (Added Line #7).

/**
	 * Define target URL and redirect customer after logging in
	 */
	protected function _loginPostRedirect()
	{
		$session = $this->_getSession();

		if (!$session->getBeforeAuthUrl() || $session->getBeforeAuthUrl() == Mage::getBaseUrl() ) {

			// Set default URL to redirect customer to
			$session->setBeforeAuthUrl(Mage::helper('customer')->getAccountUrl());

			// Redirect customer to the last page visited after logging in
			if ($session->isLoggedIn())
			{
				if (!Mage::getStoreConfigFlag('customer/startup/redirect_dashboard')) {
					if ($referer = $this->getRequest()->getParam(Mage_Customer_Helper_Data::REFERER_QUERY_PARAM_NAME)) {
						$referer = Mage::helper('core')->urlDecode($referer);
						if ($this->_isUrlInternal($referer)) {
							$session->setBeforeAuthUrl($referer);
						}
					}
				}
				else if ($session->getAfterAuthUrl()) {
					$session->setBeforeAuthUrl($session->getAfterAuthUrl(true));
				}
			} else {
				$session->setBeforeAuthUrl(Mage::helper('customer')->getLoginUrl());
			}
		} else if ($session->getBeforeAuthUrl() == Mage::helper('customer')->getLogoutUrl()) {
			$session->setBeforeAuthUrl(Mage::helper('customer')->getDashboardUrl());
		}
		else {
			if (!$session->getAfterAuthUrl()) {
				$session->setAfterAuthUrl($session->getBeforeAuthUrl());
			}
			if ($session->isLoggedIn()) {
				$session->setBeforeAuthUrl($session->getAfterAuthUrl(true));
			}
		}
		// Changed Here
		return $session->getBeforeAuthUrl(true);
	}

You can download the code From Here.

Hope it helps! Happy Coding.

 <core>
 <rewrite>
 <locale>Namespace_Module_Model_Locale</locale>
 </rewrite>
 </core>
 

Then in Namespace_Module_Model_Locale class you can add the following code.

 class Namespace_Module_Model_Locale extends Mage_Core_Model_Locale{
 /*
 * Code: subesh.com.np
 */

public function currency($currency)
 {
 Varien_Profiler::start('locale/currency');
 if (!isset(self::$_currencyCache[$this->getLocaleCode()][$currency])) {
 try {
 $currencyObject = new Zend_Currency($currency, $this->getLocale());

// Additionally Added Code
 // The options array's position key has other values as well.

// 	Zend_Currency::STANDARD
 // 	Zend_Currency::RIGHT
 //	Zend_Currency::LEFT

$options = array(
 'position'	=> Zend_Currency::RIGHT
 );

$currencyObject->setFormat($options);

// END Additionally Added Code

} catch (Exception $e) {
 $currencyObject = new Zend_Currency($this->getCurrency(), $this->getLocale());
 $options = array(
 'name'      => $currency,
 'currency'  => $currency,
 'symbol'    => $currency
 );
 $currencyObject->setFormat($options);
 }

self::$_currencyCache[$this->getLocaleCode()][$currency] = $currencyObject;
 }
 Varien_Profiler::stop('locale/currency');
 return self::$_currencyCache[$this->getLocaleCode()][$currency];
 }

}

You can see the comment of the code above for more detail understanding.

P.S: Be informed that you need to change the Class Name you are about to create on the basis of your Namespace and Module name.

/*** Setting Default Shipping Method
 * Checking If Quote Already Has Address Or Not
 * - If Yes then leave as it is
 * - Else check if Customer has default Shipping Address or Not
 * -- Yes then get Default Shipping Address and set Shipping Method
 * -- No Set Default Shipping address to NL*/
 if(!Mage::getSingleton('checkout/type_onepage')->getQuote()->getShippingAddress()->getCountryId()){
		$customerSession=Mage::getSingleton("customer/session");
		if($customerSession->isLoggedIn()){
		$customerAddress=$customerSession->getCustomer()->getDefaultShippingAddress();
			if($customerAddress->getId()){
			$customerCountry=$customerAddress->getCountryId();
				$shipping = Mage::getSingleton('checkout/type_onepage')->getQuote()->getShippingAddress()->setCountryId($customerCountry)->setShippingMethod('flatrate_flatrate')->save();
		}else{
			$shipping = Mage::getSingleton('checkout/type_onepage')->getQuote()->getShippingAddress()->setCountryId('NL')->setShippingMethod('flatrate_flatrate')->save();
			}
		}
	}

Cheers!

[UPDATE]
The original solution seems to show some issue. Thanks to the great reader of this blog the “perfect” solution for this case can be found in comments. As always new and better solutions are always welcome.

Almost all the collections found inside app/code/codepool/Namespace/Module/Model/Mysql4/model/Collection.php are the child of parent Class Mage_Core_Model_Mysql4_Collection_Abstract. Primary thing done in the class constructor is initializing its resource and Model. If you look into one of the Collection class you can see in its constructor.

/**
	 * @class Mage_Checkout_Model_Mysql4_Agreement_Collection
     * Initialize resource
     *
     */
    protected function _construct()
    {
        $this->_init('checkout/agreement');
    }

And this _init function has been implemented in its parent class as

/**
     * Standard resource collection initalization
     *
     * @param string $model
     * @return Mage_Core_Model_Mysql4_Collection_Abstract
     */
    protected function _init($model, $resourceModel=null)
    {
        $this->setModel($model);
        if (is_null($resourceModel)) {
            $resourceModel = $model;
        }
        $this->setResourceModel($resourceModel);
        return $this;
    }

The resource class can be found in app/code/codepool/Namespace/Module/Model/Mysql4/model.php. And this resource class in turn initializes the database table to be used in the Module along with the table’s primary key.

class Mage_Checkout_Model_Mysql4_Agreement extends Mage_Core_Model_Mysql4_Abstract
	{

	protected function _construct()
    {
        $this->_init('checkout/agreement', 'agreement_id');
    }
	......
	}

It is this resource class that actually works out the database connections, read/write adapters and performs transactions. So this is the basic deduction about the link of collection with the database and its tables. But how are those collection formed still remains a mystery, not anymore! In this section of the post I will try to explain how are the collections really formed.

If I can, “collection” can be defined as collection or array of its resource. And in Magento case, most of the resources are database’s query results. Simply you can visualize “collection” to be array of your model’s resource. If a “query” in Magento returns a collection of all the products then it would mean that the very collection is an array of all the individual product’s object. But one question still remains how will the database query’s result transform into a Magento “collection“. To understand that we need to understand the collection class and its parents.

The class Structure for Mage_Core_Model_Mysql4_Collection_Abstract is like this.

Mage_Core_Model_Mysql4_Collection_Abstract

|__ Varien_Data_Collection_Db (C)

|__ Varien_Data_Collection (C)

|__ IteratorAggregate (I)

|__ Countable (I)

You can see that all collection implements two Interfaces IteratorAggregate & Countable.

IteratorAggregate is predefined in Standard PHP Library that extends Abstract Base Class Traversable . On using this Interface you can then Iterate Through Object using “foreach” construct. Countable returns the size of the Collection Object.

Among the two Interfaces, IteratorAggregate is particularly important. As you can see in Class Hierarchy both the interfaces are implemented by Varien_Data_Collection concrete class. IteratorAggregate has abstract public method getIterator() which returns the Iterator interface and the concrete Class has to implement the method on its own. It is this Iterator that provides the real iteration functionality. You can get a detailed description about Iterator Here.

So if you look into the Varien_Data_Collection you will find the getIterator() implemented like this.

/**
	 * @class Varien_Data_Collection
     * Implementation of IteratorAggregate::getIterator()
     */
    public function getIterator()
    {
        $this->load();
        return new ArrayIterator($this->_items);
    }

As you can see that it first loads the “items” (I will get back to this Items) and instanciates the value to an internal Class ArrayIterator . And the Iterator returned by this function can then be iterated using foreach construct.

Looks like it is going to be a looonnnnng post, let be summarize what I’ve tried to point out until now. I’ve tried to show the link between the collection class or rather object with the database table and explain the iteration behavior of the collection object. But one question still remains how will the database query’s result transform into a Magento’s “collection“. This is where the “items” explanation need to be done.

“Items” are actually array if individual object (item) of the collection which represents the array of tuple of the database query result. As you see in the snippet above the ArrayIterator takes $this->_items are parameter. But $this->_items are not populated here on Varien_Data_Collection but rather on is child class Varien_Data_Collection_Db. Here’s the snippet from Varien_Data_Collection_Db.

/**
     * Load data
     * @class Varien_Data_Collection_Db
     * @return  Varien_Data_Collection_Db
     */
    public function load($printQuery = false, $logQuery = false)
    {
        if ($this->isLoaded()) {
            return $this;
        }

        $this->_renderFilters()
             ->_renderOrders()
             ->_renderLimit();

        $this->printLogQuery($printQuery, $logQuery);

		// Getting Data from DB
        $data = $this->getData();

        $this->resetData();

        if (is_array($data)) {

		    // Looping on each result row
            foreach ($data as $row) {
			    // Creating Empty "item" Varien_Object's object
                $item = $this->getNewEmptyItem();

                if ($this->getIdFieldName()) {
                    $item->setIdFieldName($this->getIdFieldName());
                }

				// Setting Varien_Object's values to that of the row
                $item->addData($row);

				/**
				* Adding the "item" to the collection @class Varien_Data_Collection
				* So while referring to $this->_items @class Varien_Data_Collection it will return array of this "item"
				*/
                $this->addItem($item);
            }

        }

        $this->_setIsLoaded();
        $this->_afterLoad();
        return $this;
    }

    /**
     * Get all data array for collection
     * @class Varien_Data_Collection_Db
     * @return array
     */
    public function getData()
    {
        if ($this->_data === null) {
            $this->_renderFilters()
                 ->_renderOrders()
                 ->_renderLimit();

			// Fetching all the row with the Select query set
            $this->_data = $this->_fetchAll($this->_select);
            $this->_afterLoadData();
        }
        return $this->_data;
    }

You can go through the inline comments I’ve added. This is it, I’ve finally worked out the explanation of structure & creation of Magento’s Collection and its iterative behavior. I’ve tried to show pictorially (below) what I have just described. Confused! Plz comment and of course please do comment if I am wrong, because there are “times” when you try to understand things even though they actually aren’t just like you think. I’d like to quote Paulo :“I see the world in terms of what I would like to see happen, not what actually does”!

<?php echo $this->getMessagesBlock()->getGroupedHtml() ?>

It did not work. Yes, after adding this block it had worked before. In my case, the probable case might be that I had called the module’s template from CMS page. In other case it should work. So, I looked for work around and the following did the trick.

// Getting Messages from Session
$messages=Mage::getSingleton("customer/session")->getMessages();

// Creating Block Mage_Core_Block_Messages
// Setting Message
// echoing the Message's HTML
echo $this->getLayout()->createBlock("core/messages")->setMessages($messages)->getGroupedHtml();

The Error/Success or Notice messages are set on session. So what I did was take those message/s from the session and create a new block, same as what $this->getMessagesBlock() might have called, and set those message to the created block and echoed its HTML.

Clever? or not?

Admin URL with Keys and Parameters

The part in “RED” are module controller(router)/action. And the part in “GREEN” is what we call as “Paramerters” and the “BLUE” part is the “Key“. The Key (which is also a URL parameter) in the URL has been added for security reasons and is checked against the session’s values for every action. If store owner does not want to use the key in admin url, then it can be set off from administrator settings.

My point in this post is, if you are a developer and creating a module that has Admin controller and you are simply calling some action of your controller lets say, mymodule/adminhtml_mycontroller/myaction/param1/1/param2/2 the it does not redirect you to your intended page, but will redirect to dashboard, IF key is enabled. You will have to add the key parameter to the URL to go to your page. So here is a simple snippet of code that will help you to build your URL with valid keys.

echo Mage::helper("adminhtml")->getUrl("mymodule/adminhtml_mycontroller/myaction/",array("param1"=>1,"param2"=>2));

The “adminhtml” helper will automatically create url with keys attached to the URL.

Next thing, if you see the key of various pages in admin you will see that those keys are not same, there is a different logic behind creating those key values. The keys generated depends upon the controller and action you are about to execute. Keys can be seperatly generated as follows.

Mage::getSingleton('adminhtml/url')->getSecretKey("adminhtml_mycontroller","myaction");

Hope this helps, and this can be particularly helpful when you are using templates in admin modules and adding buttons to redirect to some other location. At least that was my case!

Suppose you want to list 5 recent post made under “news” category identifier. Here’s how you can do it easily, of course you have to install the module first. The Module can be currently downloaded from Here, and will be soon available in Magento Connect as well.

<reference name="right">
	<block type="sbloghelper/helper" name="news.list">
		<action method="addCategoryIdentifier">
			<identifier>news</identifier>
		</action>
		<action method="addListSize">
			<size>5</size>
		</action>
	</block>
</reference>

Simple isn’t it? You can place similar kind of code in layout out to list other post categorically. Hope this helps to someone. Please do post your feedbacks.

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