diff --git a/dblayer.php b/dblayer.php
index 53425e2..a4bf152 100644
--- a/dblayer.php
+++ b/dblayer.php
@@ -437,21 +437,31 @@ class dblayer extends PDO
     // Check if the foreign keys constrains are valid before doing the insertion
     foreach ($this->foreign as $foreign=>$data)
     {
-      if ($this->debug) echo "   verify foreign $foreign\n";
-      if (! isset ($datas[$foreign]))
+      if ($updatekey === false)
       {
-        $errors[] = array ("error", sprintf (dgettext("domframework",
-                             "The foreign column '%s' is not provided"),
-                             $foreign));
-        return $errors;
+        // Before doing the insert, check the foreign keys. In update, they are
+        // not mandatory and are not checked for existancy.
+        if ($this->debug) echo "   verify foreign $foreign\n";
+        if (! isset ($datas[$foreign]))
+        {
+          $errors[] = array ("error", sprintf (dgettext("domframework",
+                               "The foreign column '%s' is not provided"),
+                               $foreign));
+          return $errors;
+        }
+        if (! isset ($datas[$foreign][0]))
+        {
+          $errors[] = array ("error", sprintf (dgettext("domframework",
+                               "The field type for column '%s' is not provided"),
+                               $foreign));
+          return $errors;
+          continue;
+        }
       }
-      if (! isset ($datas[$foreign][0]))
+      else
       {
-        $errors[] = array ("error", sprintf (dgettext("domframework",
-                             "The field type for column '%s' is not provided"),
-                             $foreign));
-        return $errors;
-        continue;
+        if (! array_key_exists ($foreign, $data))
+          continue;
       }
       $table = $data[0];
       $column = $data[1];