以广州旅游业为背景，设计一个变长记录文件存取类库。程序采用B+树作为索引系统，支持字节流嵌入方式和文件链接方式，以较友好的用户界面，加强程序容错性-Guangzhou tourism industry as the background, to design a variable-length record file access library. Program uses B+ tree as an indexing system to support byte-stream mode and