Magento – Calling Load with Attribute Name

productproduct-attribute

Looking through one of the projects I've been working on, I keep coming across code that does $product->load('attribute_name'), where product is an instance of Mage_Catalog_Model_Product. Digging down through the code for a product model, I fail to see what this is supposed to do. Is this just a misunderstanding by whoever wrote this custom code, or am I missing something?

As far as I'm concerned this would attempt to load a product with the id of 'attribute_code', which doesn't exist. In this situation it would hit Mage_Eav_Model_Entity_Abstract::load with $product, 'attribute_code', array() as the arguments. This would actually mark the current model as new with isObjectNew(true) since it can't be loaded from the database, but since $attributes is empty it will trigger Mage_Eav_Model_Entity_Abstract::loadAllAttributes, which due to the fact the model was partly loaded and thus contains an entity_id already, fetches all attributes from the database for that entity_id. If this is the case, the string 'attribute_code' is somewhat irrelevant (so long as it isn't the entity_id of another product) and all attributes will be loaded for the entity_id contained in the model.

Is my understanding correct, or am I missing something?

Best Answer

In short, yes what you are suggesting is correct. The select statement built when calling the load in you question would be the following.

SELECT `catalog_product_entity`.* FROM `catalog_product_entity` WHERE (entity_id ='attribute_name')

You can find this out by adding some debug into the load method in Mage_Eav_Model_Entity_Abstract

If you are actually wanting to load a product via an attribute that is not entity_id the the following snippet would do it.

Mage::getModel('catalog/product')->loadByAttribute('sku', 'My Sku Value');

NOTE: with loadByAttribute if the attribute is not unique then the first object found will be returned

SECOND NOTE: this will return either an object or false (thanks Fabian)

Related Solutions

Magento – Product load event – regardless of context

You don't need an observer to do this. You can use the attribute backend_model to handle your logic.

If you specify a backend_model with your attribute and you extend the Mage_Eav_Model_Entity_Attribute_Backend_Abstract class within your backend model class you can use the afterLoad, beforeSave, afterSave, beforeDelete or afterDelete methods to execute your own logic.

Using the backend_model is the correct way to implement this sort of logic and is how native Magento attributes do it where they have similiar requirements.

Magento 1 – Call getMinimalPrice() on Single Product Entity with Tier Prices

I didn't find a simple method to load the index for a single product, the safest bet should be using a collection.

This helper method worked for me:

/**
 * Loads minimal price from index in single product entity
 *
 * @param Mage_Catalog_Model_Product $product
 * @return $this
 */
public function loadPriceIndex(Mage_Catalog_Model_Product $product)
{
    $productCollection = $product->getCollection();
    $productCollection->addAttributeToSelect([])
        ->addAttributeToFilter('entity_id', $product->getId())
        ->addPriceData();
    $product->addData($productCollection->getFirstItem()->getData());
    return $this;
}

Don't worry about database load, this results in a single query with only one join on the price index table like this:

SELECT `e`.*, price_index.price AS `indexed_price`, `price_index`.`price`, `price_index`.`final_price`,
    IF(`price_index`.`tier_price`,
        LEAST(`price_index`.`min_price`, `price_index`.`tier_price`), 
        `price_index`.`min_price`
    ) AS `minimal_price`,
    `price_index`.`min_price`, `price_index`.`max_price`, `price_index`.`tier_price`
FROM `catalog_product_entity` AS `e`
INNER JOIN `catalog_product_index_price` AS `price_index`
ON price_index.entity_id = e.entity_id
    AND price_index.website_id = '5'
    AND price_index.customer_group_id = 0
WHERE (`e`.`entity_id` = '2026')

Best Answer

Related Solutions

Magento – Product load event – regardless of context

Magento 1 – Call getMinimalPrice() on Single Product Entity with Tier Prices

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