diff --git a/inc/migration.class.php b/inc/migration.class.php
index 0c2f889d..d8e890b9 100644
--- a/inc/migration.class.php
+++ b/inc/migration.class.php
@@ -67,7 +67,7 @@ public static function getSQLFields(string $field_name, string $field_type): arr
                 $fields[$field_name] = 'INT NOT NULL DEFAULT 0';
                 break;
             case $field_type === 'glpi_item':
-                $fields[sprintf('itemtype_%s', $field_name)] = "varchar(100) NOT NULL DEFAULT ''";
+                $fields[sprintf('itemtype_%s', $field_name)] = "varchar(100) DEFAULT NULL";
                 $fields[sprintf('items_id_%s', $field_name)] = "int {$default_key_sign} NOT NULL DEFAULT 0";
                 break;
             case $field_type === 'date':
diff --git a/templates/container.class.tpl b/templates/container.class.tpl
index e4327acd..dd76aa9e 100644
--- a/templates/container.class.tpl
+++ b/templates/container.class.tpl
@@ -33,8 +33,8 @@ class %%CLASSNAME%% extends CommonDBTM
             if ($DB->numrows($result) > 0) {
                while ($data = $DB->fetchAssoc($result)) {
                   //set default value for type 'glpi_item'
-                  if (str_starts_with($data['Field'], 'itemtype_') ) {
-                     $migration->changeField($table, $data['Field'], $data['Field'], "varchar(100) NOT NULL DEFAULT ''");
+                  if (str_starts_with($data['Field'], 'itemtype_')) {
+                     $migration->changeField($table, $data['Field'], $data['Field'], "varchar(100) DEFAULT NULL");
                      $migration->migrationOneTable(self::getTable());
                   }
                }