MAPGIS OLE DB提供者的设计与实现

OLE DB是微软公司的通用数据存取策略(UDA)的重要组成部分, 简要介绍了OLE DB在UDA中的地位和作用, 以及OLE DB提供者的基本原理.针对MAPGIS地理信息系统用Ⅵ-SUALC+ + ATL设计了一个OLE DB提供者, 该提供者能够根据MAPGIS数据的结构动态读取常规类型的字段值.重点介绍了该OLE DB提供者的数据源对象、会话对象、命令对象和行集对象的设计方法.该OLE DB提供者是一个只读型的提供者, 它比较适合于只对数据进行查询的应用, 在VB环境下能够进行快速开发, 甚至不用编程便能够提取MAPGIS数据进行表格输出或自动生成发布网页. 

Design and Implementation of MAPGIS OLE DB Provider

The authors of this paper introduce briefly the level, functions and basic principle of OLE DB in Microsoft UDA, which is an important part of Microsoft UDA.They design an OLE DB provider for MAPGIS with VISU-AL C+ + ATL, which can get value of normal type of field according to MAPGIS data structure.They emphasize in particular the design of the provider's data-source object, session object, command object and rowset object.A readonly provider is very useful for the application which only needs data-query, and can be rapidly developed with VB programming environment. Itmay even enable the user to get MAPGIS data to make output tables orWeb page automatically without programming.