研究了动态连续场模型的地理信息的表达及其在空间数据库中的存储、访问和操作,提出了构建解析式表达的动态连续场抽象数据类型,在对象关系数据库中实现该类型的扩展,定义一系列动态连续场上的操作,并对结构化查询语言(SQL)进行扩展的方法,进而在PostgreSQL上实现了解析式表达动态连续场的基本数据类型扩展及一系列函数扩展,支持动态连续场对象的表达和操作,并通过实例演示了扩展SQL语句的功能。结果表明,将动态连续场用解析式表达并在空间数据库中实现扩展,不仅为动态场模型数据提供了完善的存储、访问和操作的机制,而且能在查询语言的层次上实现场模型数据和各类空间数据的集成应用,借助扩展SQL语言来实现面向问题的非过程化空间信息一体化处理。
A new method of constructing analytical dynamic continuous field (ADCF) data type was introduced to research on the representation of geographic information based on dynamic continuous field and its storage, query and manipulation in spatial database. The functions of ADCF data type consisted of continuous spatiotemporal functions and a series of operatots. The ADCF data type and function extensions were implemented in an object-relational spatial database, and accordingly the Structure Query Language (SQL) was strengthened to utilize this new data type. Several application examples demonstrated the SQL extended functions of ADCF. The method not only provides a good way to store, access and manipulate dynamic-field-model-based data, but also implements the integrative applications of field data and other kinds of spatial data from query language level. It helps solve integrative transactions on question-oriented and nonprocedural spatial information.