diff --git a/apachesolr_attachments.install b/apachesolr_attachments.install
index 08887ab..08978d2 100644
--- a/apachesolr_attachments.install
+++ b/apachesolr_attachments.install
@@ -96,13 +96,15 @@ function apachesolr_attachments_schema() {
           'description' => t('The type of entity.'),
           'type' => 'varchar',
           'length' => 128,
-          'not null' => FALSE,
+          'not null' => TRUE,
+          'default' => '',
         ),
         'parent_entity_id' => array(
           'description' => t('The type of the parent entity.'),
           'type' => 'int',
           'unsigned' => TRUE,
-          'not null' => FALSE,
+          'not null' => TRUE,
+          'default' => 0,
         ),
         'hash' => array(
           'description' => "A hash of the file's body, to check for changes.",