Index: modules/taxonomy/taxonomy.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/taxonomy/taxonomy.install,v
retrieving revision 1.31
diff -u -r1.31 taxonomy.install
--- modules/taxonomy/taxonomy.install	30 Dec 2009 08:12:20 -0000	1.31
+++ modules/taxonomy/taxonomy.install	5 Jan 2010 19:10:32 -0000
@@ -203,6 +203,7 @@
         'default'=> 0,
       ),
     ),
+    'primary key' => array('tid', 'vid'),
     'indexes' => array(
       'term_node' => array('tid', 'sticky', 'created'),
     ),
@@ -437,3 +438,9 @@
   db_add_index('taxonomy_term_data', 'name', array('name'));
 }
 
+/**
+ * Add a primary key to the {taxonomy_index} table
+ */
+function taxonomy_update_7008() {
+  db_add_primary_key('taxonomy_index', array('tid', 'vid'));
+}
\ No newline at end of file