Like other relational database management systems such as Oracle and SQL Server, Informix has its internal optimizer, which is responsible for selecting the best query execution plan.
与Oracle和SQLServer等其他关系数据库管理系统一样，Informix也有内部优化器，负责选择最佳的查询执行计划。
Using XQuery (a functional language designed to query collections of XML data) with native XML database systems can be extremely useful in some situations.
在某些情况下，在原生XML数据库系统中使用XQuery（一种用于查询 XML数据集合的函数型语言）可能非常有用。
For the distributed database systems, query processing becomes more difficult because of distribution and redundance of data.
在分布式数据库系统中，由于数据的分布和冗余，查询处理变得更为复杂。
Query optimization is the critical technique of parallel database systems.
查询优化是并行数据库系统的核心技术。
In this paper, we describe an algorithm, for query processing with semantic optimization in distributed relational database systems.
本文描述一个分布式关系数据库系统中具有语义优化的查询处理算法。
The near neighbor pair query of the datasets in the network has important application in geographical information systems, query in the network and spatial database.
网络环境下的数据集中的近邻对查询在地理信息系统、网络查询和空间数据库等领域有着重要的应用。
Query optimization and processing is a critical component of parallel database systems.
查询优化和处理是并行数据库管理系统的关键组成部分。
This paper discusses the understanding on the parallel database from the architecture of parallel database systems, parallel database query, aggregation, sorting, and data reliability.
本文从并行数据库系统的体系结构、并行数据库的查询，聚集，排序及数据可靠性等方面入手，阐述了对并行数据库的认识和看法。
This paper proposes a triggered dynamic query re-optimization for very long-running queries in database systems.
对数据库系统内长期运行的查询处理的查询优化提出了一种触发的动态查询再优化方法。
Emphasis on spatial analysis using geographic information systems and database query tools.
本课程将强调利用区域资料系统和数据库查询工具进行空间分析。
The major task of on-line operational database systems is to perform on-line transaction and query processing.
联机操作数据库系统的主要任务是执行联机事务和查询处理。
In many current multimedia database systems, query or retrieval is only based on descriptive KeyWords of media, it ignores another important information resource the content of media.
现有的许多多媒体数据库系统只提供了基于媒体描述关键字的检索和查询，却忽略了另一个重要的信息来源——媒体的内容。
Histogram is the common method for size estimation of query result in many commercial database systems.
直方图是许多商用数据库系统中最常用的一种估算查询结果大小的方法。
The query processing in the distributed database systems is comprehensively summarized. This paper shows that using HASHING method for thereduction of semi-join communication cost is beneficial.
本文较全面地总结了分布式数据库系统的查询处理，并提出用HASHING方法减少半连接通讯的开销是有利的。
The query speed is one of the most important criteria in database systems.
查询速度是数据库系统中最重要的指标之一。
Query optimization for large join queries is one of the key factors to improving the performance of database systems.
多连接查询优化是提高数据库性能的关键问题之一。
Query optimization for large join queries is one of the key factors to improving the performance of database systems.
多连接查询优化是提高数据库性能的关键问题之一。
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