Refactor migrations with $up & $down

system/migrations/33.php

@@ -1,12 +1,16 @@
 <?php
+/**
+ * @var OTS_DB_MySQL $db
+ */
+
 // Increase size of ip in myaac_visitors table
 // according to this answer: https://stackoverflow.com/questions/166132/maximum-length-of-the-textual-representation-of-an-ipv6-address
 // the size of ipv6 can be maximal 45 chars
 
 $up = function () use ($db) {
-	$db->exec('ALTER TABLE `' . TABLE_PREFIX . "visitors` MODIFY `ip` VARCHAR(45) NOT NULL;");
+	$db->modifyColumn(TABLE_PREFIX . 'visitors', 'ip', 'VARCHAR(15) NOT NULL');
 };
 
-$down = function () {
+$down = function () use ($db) {
 	// nothing to be done, as we have just extended the size of a column
 };