/**
  * return primary if set, false otherwise
  *
  * @uses    PMA_Index::_loadIndexes()
  * @uses    PMA_Index::$_registry
  * @param   string $table
  * @param   string $schema
  * @return  mixed primary index or false if no one exists
  */
 public static function getPrimary($table, $schema)
 {
     PMA_Index::_loadIndexes($table, $schema);
     if (isset(PMA_Index::$_registry[$schema][$table]['PRIMARY'])) {
         return PMA_Index::$_registry[$schema][$table]['PRIMARY'];
     } else {
         return false;
     }
 }