public function describeIndexes($conn, $table, $schema = null)
    {
        $dialect = $conn->getDialectType();
        $method = 'describeIndexes' . $dialect;
        if (!method_exists($this, $method)) {
            throw new Exception("Describe index for $dialect is not implemented yet");
        }
        return $this->$method($conn, $table, $schema);
    }