diff --git a/lib/xmldb/classes/generators/mssql/mssql.class.php b/lib/xmldb/classes/generators/mssql/mssql.class.php
index 5b6c7073a3a..9d92171b9da 100644
--- a/lib/xmldb/classes/generators/mssql/mssql.class.php
+++ b/lib/xmldb/classes/generators/mssql/mssql.class.php
@@ -229,10 +229,12 @@ class XMLDBmssql extends XMLDBgenerator {
         if ($xmldb_field->getEnum()) {
         /// Drop the current enum (not needed, it has been dropped before for msqql (in getRenameFieldSQL)
             //$results = array_merge($results, $this->getDropEnumSQL($xmldb_table, $xmldb_field));
-        /// Change field name
-            $xmldb_field->setName($newname);
+        /// Change field name (over a clone to avoid some potential problems later)
+            $new_xmldb_field = clone($xmldb_field);
+            $new_xmldb_field->setName($newname);
+
         /// Recreate the enum
-            $results = array_merge($results, $this->getCreateEnumSQL($xmldb_table, $xmldb_field));
+            $results = array_merge($results, $this->getCreateEnumSQL($xmldb_table, $new_xmldb_field));
         }
 
         return $results;
diff --git a/lib/xmldb/classes/generators/oci8po/oci8po.class.php b/lib/xmldb/classes/generators/oci8po/oci8po.class.php
index 97d462e49e3..41d5144dc17 100644
--- a/lib/xmldb/classes/generators/oci8po/oci8po.class.php
+++ b/lib/xmldb/classes/generators/oci8po/oci8po.class.php
@@ -214,10 +214,11 @@ class XMLDBoci8po extends XMLDBgenerator {
         if ($xmldb_field->getEnum()) {
         /// Drop the current enum
             $results = array_merge($results, $this->getDropEnumSQL($xmldb_table, $xmldb_field));
-        /// Change field name
-            $xmldb_field->setName($newname);
+        /// Change field name (over a clone to avoid some potential problems later)
+            $new_xmldb_field = clone($xmldb_field);
+            $new_xmldb_field->setName($newname);
         /// Recreate the enum
-            $results = array_merge($results, $this->getCreateEnumSQL($xmldb_table, $xmldb_field));
+            $results = array_merge($results, $this->getCreateEnumSQL($xmldb_table, $new_xmldb_field));
         }
 
         return $results;
diff --git a/lib/xmldb/classes/generators/postgres7/postgres7.class.php b/lib/xmldb/classes/generators/postgres7/postgres7.class.php
index e24e7c48f19..6cf983b5fb5 100644
--- a/lib/xmldb/classes/generators/postgres7/postgres7.class.php
+++ b/lib/xmldb/classes/generators/postgres7/postgres7.class.php
@@ -370,10 +370,11 @@ class XMLDBpostgres7 extends XMLDBgenerator {
         if ($xmldb_field->getEnum()) {
         /// Drop the current enum
             $results = array_merge($results, $this->getDropEnumSQL($xmldb_table, $xmldb_field));
-        /// Change field name
-            $xmldb_field->setName($newname);
+        /// Change field name (over a clone to avoid some potential problems later)
+            $new_xmldb_field = clone($xmldb_field);
+            $new_xmldb_field->setName($newname);
         /// Recreate the enum
-            $results = array_merge($results, $this->getCreateEnumSQL($xmldb_table, $xmldb_field));
+            $results = array_merge($results, $this->getCreateEnumSQL($xmldb_table, $new_xmldb_field));
         }
 
         return $results;