diff --git a/viewfield.install b/viewfield.install
index d536053..e20c3c6 100644
--- a/viewfield.install
+++ b/viewfield.install
@@ -108,7 +108,7 @@ function viewfield_update_6001() {
         db_change_field($ret, $table_name, $vname_info['column'], $vname_info['column'], array(
           'type' => 'varchar',
           'length' => $new_length,
-          'not null' => TRUE,
+          'not null' => FALSE,
           'default' => '',
         ));
       }
@@ -116,4 +116,3 @@ function viewfield_update_6001() {
   }
   return $ret;
 }
-