diff --git a/dblayeroo.php b/dblayeroo.php
index 600a93e..ef8663e 100644
--- a/dblayeroo.php
+++ b/dblayeroo.php
@@ -2583,7 +2583,13 @@ class dblayeroo
       if ($update)
       {
         // Can not update multiple UNIQUE rows with the same value
-        $cols = explode (",", $columns);
+        if (is_string ($columns))
+          $cols = explode (",", $columns);
+        elseif (is_array ($columns))
+          $cols = $columns;
+        else
+          $this->DBException (dgettext ("domframework",
+            "Unique def is not a string or an array"));
         foreach ($cols as $col)
         {
           if (!key_exists ($col, $setValues))