diff --git a/lib/dmllib.php b/lib/dmllib.php
index 64a39ae80ec..cf876d88ca9 100644
--- a/lib/dmllib.php
+++ b/lib/dmllib.php
@@ -37,6 +37,15 @@
 
 require_once($CFG->libdir.'/dml/moodle_database.php');
 
+/**
+ * DML exception class, use instead of error() in dml code.
+ */
+class dml_exception extends moodle_exception {
+    function __construct($errorcode, $a=NULL, $debuginfo=null) {
+        parent::__construct($errorcode, '', '', $a, $debuginfo);
+    }
+}
+
 /**
  * Sets up global $DB moodle_database instance
  * @return void