diff --git a/core/includes/common.inc b/core/includes/common.inc
index 9d498c2..d262fc9 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -7093,6 +7093,9 @@ function _drupal_schema_initialize(&$schema, $module, $remove_descriptions = TRU
  */
 function drupal_schema_fields_sql($table, $prefix = NULL) {
   $schema = drupal_get_schema($table);
+  if (empty($schema['fields'])) {
+    $schema = drupal_get_schema($table, TRUE);
+  }
   $fields = array_keys($schema['fields']);
   if ($prefix) {
     $columns = array();