magento store data in custom columns - magento

Question

I added two text columns to sales_flat_quote_item in order to store data and for other reasons When i add product to cart. my problem is that i cant save the data. i tried a lot of examples but without any success.
here i add the coulmns :
$installer = $this;
$connection = $installer->getConnection();
$installer->startSetup();
$installer->getConnection()
->addColumn($installer->getTable('sales/quote_item'),
'pack_name',
array(
'type' => Varien_Db_Ddl_Table::TYPE_TEXT,
'nullable' => true,
'default' => null,
'comment' => 'pack_name'
)
);
$installer->endSetup()
;
this is the code in my observer where i try to save the data :
$quote_item = Mage::getModel('sales/quote_item')->load($quote->Id);
$quote_item->setPackName($string);
$quote_item->save();
any help?

Answer 1

It's not advisable to add columns to flat tables like this. The magic methods aren't working because your update to the schema goes against Magento best practices. If you just want a quick fix though, you can do it with raw SQL queries:
<?php
$transaction = Mage::getSingleton('core/resource')->getConnection('core_write');
try {
$transaction->beginTransaction();
$query_string = "UPDATE sales_flat_quote_item
SET pack_name='packname'
WHERE id='id'";
$transaction->query($query_string);
$transaction->commit();
}
catch (Exception $e) {
$transaction->rollBack();
}
Be careful though, it's not secure. Make sure your data is sanitized.