diff --git a/lib/xmldb/xmldb_field.php b/lib/xmldb/xmldb_field.php
index ceffdc413ba..13f45467593 100644
--- a/lib/xmldb/xmldb_field.php
+++ b/lib/xmldb/xmldb_field.php
@@ -481,11 +481,6 @@ class xmldb_field extends xmldb_object {
             $notnull = 'false';
         }
         $o.= ' NOTNULL="' . $notnull . '"';
-        if ($this->unsigned) {
-            $unsigned = 'true';
-        } else {
-            $unsigned = 'false';
-        }
         if ($this->type == XMLDB_TYPE_INTEGER ||
             $this->type == XMLDB_TYPE_NUMBER ||
             $this->type == XMLDB_TYPE_FLOAT) {
diff --git a/lib/xmldb/xmldb_file.php b/lib/xmldb/xmldb_file.php
index c80356f095d..a505e7aadb9 100644
--- a/lib/xmldb/xmldb_file.php
+++ b/lib/xmldb/xmldb_file.php
@@ -171,8 +171,6 @@ class xmldb_file extends xmldb_object {
      */
     function saveXMLFile() {
 
-        $result = true;
-
         $structure =& $this->getStructure();
 
         $result = file_put_contents($this->path, $structure->xmlOutput());
diff --git a/lib/xmldb/xmldb_object.php b/lib/xmldb/xmldb_object.php
index f0e0dc1acd6..9fa99822d9b 100644
--- a/lib/xmldb/xmldb_object.php
+++ b/lib/xmldb/xmldb_object.php
@@ -433,8 +433,6 @@ class xmldb_object {
      */
     function comma2array($string) {
 
-        $arr = array();
-
         $foundquotes  = array();
         $foundconcats = array();
 
diff --git a/lib/xmldb/xmldb_structure.php b/lib/xmldb/xmldb_structure.php
index d966a64e4f6..41e48bb12d8 100644
--- a/lib/xmldb/xmldb_structure.php
+++ b/lib/xmldb/xmldb_structure.php
@@ -162,8 +162,6 @@ class xmldb_structure extends xmldb_object {
         $table =& $this->getTable($tablename);
         if ($table) {
             $i = $this->findTableInArray($tablename);
-            $prevtable = NULL;
-            $nexttable = NULL;
         /// Look for prev and next table
             $prevtable =& $this->getTable($table->getPrevious());
             $nexttable =& $this->getTable($table->getNext());
diff --git a/lib/xmldb/xmldb_table.php b/lib/xmldb/xmldb_table.php
index 8f3712c5c2c..6dcbfe1d181 100644
--- a/lib/xmldb/xmldb_table.php
+++ b/lib/xmldb/xmldb_table.php
@@ -344,8 +344,6 @@ class xmldb_table extends xmldb_object {
         $field =& $this->getField($fieldname);
         if ($field) {
             $i = $this->findFieldInArray($fieldname);
-            $prevfield = NULL;
-            $nextfield = NULL;
         /// Look for prev and next field
             $prevfield =& $this->getField($field->getPrevious());
             $nextfield =& $this->getField($field->getNext());
@@ -375,8 +373,6 @@ class xmldb_table extends xmldb_object {
         $key =& $this->getKey($keyname);
         if ($key) {
             $i = $this->findKeyInArray($keyname);
-            $prevkey = NULL;
-            $nextkey = NULL;
         /// Look for prev and next key
             $prevkey =& $this->getKey($key->getPrevious());
             $nextkey =& $this->getKey($key->getNext());
@@ -406,8 +402,6 @@ class xmldb_table extends xmldb_object {
         $index =& $this->getIndex($indexname);
         if ($index) {
             $i = $this->findIndexInArray($indexname);
-            $previndex = NULL;
-            $nextindex = NULL;
         /// Look for prev and next index
             $previndex =& $this->getIndex($index->getPrevious());
             $nextindex =& $this->getIndex($index->getNext());