B树及其在MINISIS中的应用

B-TREE AND ITS USE IN MINISIS

在联机情报检素系统中，倒排文件的组织可用B树来实现。由于B树具有要求较少的内存、最少的二级存贮器存取次数、快速的树搜索、简单的更新算法和有效地在联机环境下被实现等优点，它已成为一个标准的文件组织，被广泛地用于用户的文件索引、数据库系统和通用存取方法中。本文将说明B树的结构、着重分析操作和维护B树的开销、B树的主要变种及优点、多用户环境下的B树、一个用B树的通用存取方法。最后，以实例说明B树在适合于书目情报检索应用的关系数据库管理系统MINISIS中的具体应用，描述了B树文件在该系统中的逻辑结构和对相对记录号的信息压缩表示。

The B-tree of Bayer and McCreight has become widely used in recent years （both in theory and in practice）ior storing and updating large amounts of information, especially on secondary storage devices. This paper consists of two sections. The first reviews the B-tree and its variations, and analyses the time and space costs of maintenance. In the second section, there is a practical application of the B-tree in MINISIS which is a relational data-base management system for bibliographic information retrieval,