def get_full_piece_id(piece):
    """
    Returns rdb piece id and append movement id if exists.

    :param piece: A piece as stored in dataset
    :return: A string containing either the piece ID (no movement information) like "123", or the piece ID followed
      by dash, followed by the movement ID like "123-46123"
    """
    piece_id_only = piece["rdb_id_piece"]
    movement_id = str(piece.get("rdb_id_movement", ""))

    piece_id = str(piece_id_only)
    if movement_id:
        piece_id += "-" + movement_id

    return piece_id