Magento SELECT via ORM - php

Question

I would like to know how can I do a SELECT from a Magento core table but not using pure SQL but using collections.
Currently, inside a class that extends Mage_Core_Model_Abstract, on a given function I have the following code:
$resource = Mage::getSingleton("core/resource");
$tableName_SalesQuoteItem = $resource->getTableName("sales/quote_item");
$readConnection = $resource->getConnection("core_read");
$sqlInstruction = "SELECT item_id FROM {$tableName_SalesQuoteItem} WHERE sku = :sku AND quote_id = :quote_id;";
$binds = array("sku" => $itemSku, "quote_id" => $quoteID);
$result = $readConnection->query($sqlInstruction, $binds);
if($row = $result->fetch()) {
$currentItemID = $row["item_id"];
}
Any ideas?
Thanks!

Answer 1

The issue appears to be is that you're trying to load the header table 'sales/quote' and call items on it, when the items are stored in the sub-table sales/quote_item
Here's a functional prototype:
<?php
require_once( 'app/Mage.php' );
umask(0);
Mage::app('default');
$sCustomerId = 1;
$oQuotes = Mage::getModel( 'sales/quote' )->getCollection();
$oQuotes->addFieldToFilter( 'customer_id', $sCustomerId );
foreach( $oQuotes as $oQuote )
{
var_dump( $oQuote->getId() );
var_dump( $oQuote->getData( 'customer_email' ) );
var_dump( $oQuote->getData( 'customer_id' ) );
$oItems = Mage::getModel( 'sales/quote_item' )
->getCollection()
->setQuote( $oQuote );
foreach( $oItems as $oItem )
{
var_dump( $oItem->getData( 'sku' ) );
var_dump( $oItem->getData( 'name' ) );
var_dump( $oItem->getData( 'description' ) );
var_dump( $oItem->getData( 'price' ) );
}
}
$iCountQuotes = $oQuotes->count();
var_dump( $iCountQuotes );
?>

Answer 2

From your question it appears that you are looking for an ORM way to achieve the same thing you are doing with your query.
Here you go:
$collection = Mage::getModel('sales/quote')->getCollection();
$collection->addAttributeToFilter('sku',$itemSku);
$collection->addAttributeToFilter('quote_id',$quoteID);
if($collection->count())
{
//Add your code here
$firstItem = $collection->getFirstItem();
print_r($firstItem);
}
Read more about Magento ORM basics here
You could alternatively try addFieldToFilter if addAttributeToFilter doesn't work.