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.