public function dropIndex($name)
    {
        if (is_array($name))
            $name = $this->name.'___'.implode('__', $name);
        elseif(!is_int(strpos($name,'___')))
            $name = $this->name.'___'.$name;
        $name = $this->db->quotekey($name);
        $table = $this->db->quotekey($this->name);
        $cmd = array(
            'pgsql|sqlite2?|ibm' =>
                "DROP INDEX $name;",
            'mssql|sybase|dblib|odbc|sqlsrv' =>
                "DROP INDEX $table.$name;",
            'mysql'=>
                "ALTER TABLE $table DROP INDEX $name;",
        );
        $query = $this->findQuery($cmd);
        $this->queries[] = $query;
    }