diff --git a/guideme.install b/guideme.install
index c9fd9ba..e98445c 100644
--- a/guideme.install
+++ b/guideme.install
@@ -21,6 +21,8 @@ function guideme_schema() {
         'guide_path' => array(
           'type' => 'varchar',
           'length' => 255,
+          'not null' => TRUE,
+          'default' => '',
         ),
       ),
       'primary key' => array('uid', 'guide_path'),