摘要： 本文描述了一个基于微机局部网的分布式数据库管理系统MDDBMS的分片透明性问题,它涉及分片定义,查询处理,离网查询优化及更新问题。分片模式包括混合分片,它从全局模式经由一系列的分片操作(垂直、水平和导出水平分片)得到。一个查询操作被转化为一棵操作树,然后对它进行优化和模拟执行。基于一系列定理和推论,本文提出了一个与网络无关的优化算法。

Abstract: The fragmentation transparency of a distributed database managenent system MODEMS in microcomputer LAN involves fragmentation definition, query process, network-free query optimization and update.' Fragmentation includes mixed one, derived from global scheme by a number of fragmentation operators-vertical/ horizontal and derived horizontal. A query operator is transformed into an operator-tree, which, after Being optimized, executes in a simulant way. A network-free optimization algorithm is obtained from a series of theorems and deductions.