function fontyourface_update_7202 in @font-your-face 7.2
Make the 'url' column unique to enable exportables
File
- ./fontyourface.install, line 262 
- Adds fontyourface tables for tracking fonts.
Code
function fontyourface_update_7202() {
  $schema = fontyourface_7200_schema();
  try {
    db_add_unique_key('fontyourface_font', 'url', array(
      'url',
    ));
  } catch (DatabaseSchemaObjectExistsException $e) {
    // Fail silently.
  }
}