Space For Expansion Based On Sql Query Analysis System Design And Research

The technology of spatial query and analyse is one of the key points in the development of Geographical Information System (GIS). At present, the study on the query model is growing rapidly. This article presents a survey of different approaches for spatial query, comparing the textual languages and representational languages. Because the Structured Query Language (SQL) is developed as the industry standard, the query model based on the extensions of SQL has become the mainstream and has been applied in the commercial GIS systems.This article discusses several important questions on the design for the query model based on the extensions of SQL, including the expressions of spatial data and spatial attribute, spatial relations and spatial query conditions. Besides the article analyses the spatial operators and related spatial index technology. Based on the above research, the article recommends a new solution for spatial query and analyse system: R-SQL.The R-SQL system is developed on the RealGIS platform for GIS. This article introduces the system's data model and architecture, which can be adapted on various data sources. As the core module of the system, the query control sub-system adopts the query decomposition theory. The article goes deep in the corresponding strategies for query optimization, including predicate optimization, query decomposition, plan generation and execution. Move over, the article introduces the cache theory and related works for dealing with huge spatial data. Finally the article provides the implementation of the system kernel modules.At the end, we look forward the future of the development of the R-SQL system and give some advice to improve the system.