gistfile1.php

<?php

    protected $_attrMap = array(
        'sku'               => 'BaseId',
        'description'       => 'Description',
        'short_description' => 'ExpWebDesc',
        'msrp'              => 'MSRP',
        // etc
    );
    public function run()
    {
        $this->_initDb();
        $stmt = $this->_db->query('SELECT * FROM product LIMIT 10');
        while ($attributes = $stmt->fetch(PDO::FETCH_ASSOC)) {
            $attrStmt = $this->_db->prepare('SELECT AttrId, Value
                FROM prodatt
                WHERE ProductId = ?');
            $attrStmt->execute(array($attributes['ProductId']));
            while ($attr = $attrStmt->fetch(PDO::FETCH_ASSOC)) {
                $attributes[$attr['AttrId']] = $attr['Value'];
            }
            $productId = Mage::getSingleton('catalog/product')->getIdBySku($attributes[$this->_attrMap['sku']]);
            if ($productId && $productId > 0) {
                $this->updateProduct($productId, $attributes);
            } else {
                $this->createProduct($attributes);
            }
        }
    }
    public function updateProduct($productId, array $attributes)
    {
        $product = Mage::getModel('catalog/product')->load($productId);
        $product = $this->_setAttributeValues($product, $attributes);
        $product->save();
    }
    public function createProduct(array $attributes)
    {
        $product = Mage::getModel('catalog/product');
        $product = $this->_setAttributeValues($product, $attributes);
        $product->save();
    }
    protected function _setAttributeValues(Mage_Catalog_Model_Product $product, array $attributes)
    {
        foreach ($this->_attrMap as $mageCode => $key) {
            switch ($mageCode) {
                // handle special attributes
                case 'type_id':
                    $product->setTypeId(psuedoGetType($attributes[$key]));
                    break;
                // cases for stock items, selects, Y/N -> 1/0, etc
                default:
                    $product->setData($mageCode, $attributes[$key]);
            }
        }
        return $product;
    }