public function copy_quote($source_id, $target_id)
    {
        $this->load->model('quotes/mdl_quote_items');

        $quote_items = $this->mdl_quote_items->where('quote_id', $source_id)->get()->result();

        foreach ($quote_items as $quote_item) {
            $db_array = array(
                'quote_id' => $target_id,
                'item_tax_rate_id' => $quote_item->item_tax_rate_id,
                'item_product_id' => $quote_item->item_product_id,
                'item_name' => $quote_item->item_name,
                'item_description' => $quote_item->item_description,
                'item_quantity' => $quote_item->item_quantity,
                'item_price' => $quote_item->item_price,
                'item_discount_amount' => $quote_item->item_discount_amount,
                'item_order' => $quote_item->item_order,
                'item_product_unit' => $quote_item->item_product_unit,
                'item_product_unit_id' => $quote_item->item_product_unit_id,
            );
      ....
    }