Query Optimization in Heterogeneous Environment

目前，用户在检索信息方面存在困难 其存储在不同类型的数据库系统中。大多数用户 不熟悉不同的查询语言， 知道数据的位置。该项目的目标是 简化查询公式并加快查询处理， 异构数据库环境，即不同类型的 数据库系统，特别是关系型的，面向对象的， 演绎系统和文本系统共存于一个组织中， 在不同的组织中。为了使熟悉 只有一种查询语言来访问存储在 不同类型的数据库系统，查询语言的翻译器 正在建造中。 构造智能数据字典， 便于模式集成和查询翻译。 查询 通过应用基于逻辑的 方法，使用以前关于查询类型的知识 已处理。不同系统间的并行处理技术 用于提供进一步的加速。 所得 异构查询处理系统将具有广泛的适用性 因为不同数据库系统的联网变得普遍。

Currently, users have difficulties in retrieving information which is stored in different types of database systems. Most users are not familiar with different query languages and may not be aware of the locations of data. The objective of this project is to facilitate query formulation and to speed up query processing in heterogeneous database environments, i.e. where different types of database systems, specifically, relational, object-oriented, deductive, and textual systems co-exist in an organization or across different organizations. To enable a user who is familiar with only a single query language to access information stored in different types of database systems, translators of query languages are being built. An intelligent data dictionary is constructed to facilitate schema integration and query translation. Query processing performance is optimized by application of logic-based methods, using knowledge about the types of queries previously processed. Parallel processing techniques across different systems are employed to provide further speedup. The resulting heterogeneous query processing system will find wide applicability as the networking of different database systems becomes widespread.