多关系子句相关的查询优化

关系数据库通过SQL语言进行查询操作.由于SQL语言是一种非过程化语言,因此,用户所编写的SQL语句一般不是最优的,于是,对SQL查询进行优化就成为数据库管理系统的任务.本文以应用实例为基础,结合数据库理论,介绍查询优化技术在多关系相关子查询中的运用.

The Optimization of the Relevant Query of Multiple Relative Clauses

The Relative Database queries and operates through SQL. Because SQL is not a processizational language, SQL sentences that users write are not generally optimum.So it becomes the task of the data base management system to optimize the inquiry about SQL. This paper introduces the application of the technology of the query's optimization in the relevant sub-query about the multiple relative clauses by using the instance as the foundation and combining the theory of the database.