Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1276
diff -u -p -r1.1276 common.inc
--- includes/common.inc	15 Dec 2010 23:50:56 -0000	1.1276
+++ includes/common.inc	17 Dec 2010 01:31:13 -0000
@@ -6620,6 +6620,13 @@ function _drupal_schema_initialize(&$sch
         unset($field['description']);
       }
     }
+    // Set the type key for all fields.
+    // Type will not exist if the field is only using DB-specific data types.
+    foreach ($table['fields'] as &$field) {
+      if (!isset($field['type'])) {
+        $field['type'] = NULL;
+      }
+    }
   }
 }