One major source of confusion, and consequent c&icisms, about object-oriented databases has been the lack of a comprehensive model of queries. Although there is a reasonable degree of agreement about an object-oriented data model, few operational systems support a query model for object-oriented databases. In this paper, we present a rather comprehensive query model which is consistent with obj...

In our efforts to develop an object-oriented visual programming language, the dataflow model of computation is extended from its traditional functional model to an object-oriented model. It is argued that the concept of subroutine in the object-oriented model requires two different types of calling (activation) mechanisms, the synchronous call and the asynchronous call. Asynchronous subroutine ...

Nowadays, there are many attempts to establish object-oriented GIS in some software However, they are not accordant to object-oriented concept whole and systematically in the whole course from the process of cognizing and abstracting geographical space to the process of defining and describing GIS data model then to the process of analyzing and designing GIS. Especially, the research on common ...