// Generate order reference durring upgrade

install-dev/php/generate_order_reference.php

@@ -0,0 +1,14 @@
+<?php
+
+function generate_order_reference()
+{
+	// Get all orders
+	$orders = Db::getInstance()->executeS('SELECT id_order FROM '._DB_PREFIX_.'orders');
+	foreach ($orders as $order)
+	{
+		Db::getInstance()->execute('
+			UPDATE '._DB_PREFIX_.'orders
+			SET reference = \''.Order::generateReference().'\'
+			WHERE id_order = '.$order['id_order']);
+	}
+}