Query Optimization in Object-Oriented Database Management Systems with Encapsulated Behavior

具有行为封装的面向对象数据库系统 支持强大的数据抽象，但通常很慢。 传统的数据库系统提供有效的查询 处理，但有限的数据建模设施。 这 一个研究项目寻求新的技术，结合联合收割机的权力， 抽象数据类型的数据库优化技术 转换成语义上强大而有效的查询和命令 处理系统 如果行为被封装，则中央查询优化器不能 语义、行为和成本的原因， 查询. 执行查询优化的关键在于 封装类型的方法是将这些信息显示给 受信任的系统组件，并确保行为 不会在启示之间改变， 评价 自句法分析的类型和行为 定义可能只产生有限的性能改进， 类型实现者将能够揭示其他相关的 信息.该项目包括定义一个 面向对象的数据语言，一种代数查询语言， 允许优化，揭示机制，可扩展的 优化器和软件原型来验证 研究概念和想法。 研究的目标是开发一种关键技术， 将允许面向对象的数据库系统与封装 行为，以获得与可扩展 关系系统，从而使这种系统可行 管理大数据量的替代方案。

Object-oriented database systems with behavioral encapsulation support powerful data abstractions but are generally slow. Conventional database systems provide efficient query processing, but limited data modeling facilities. This research project seeks new techniques that combine the power of abstract data types with database optimization technology into a semantically powerful and efficient query and command processing system. If behavior is encapsulated, a central query optimizer cannot reason about semantics, behavior, and cost over an entire query. The key to performing optimization of queries over encapsulated types is in revealing such information to a trusted system component, and in ensuring that the behavior will not change between the points of revelation and evaluation. Since syntactic analysis of type and behavior definition may yield only limited performance improvement, the type implementor will be able to reveal other relevant information. The project includes the definition of an object-oriented data language, an algebraic query language that permits optimization, a revealing mechanism, an extensible optimizer, and a software prototype to validate the investigated concepts and ideas. The goal of the research is to develop a key technique that will allow object-oriented database systems with encapsulated behavior to attain performance comparable to extensible relational systems, thus making such systems viable alternatives for managing large data volumes.