变化的业务需求不断地要求向关系数据模型或面向对象模型中添加新实体和关系。
From time to time, the demands of changing business needs require that you add new entities and relationships to the relational data models or object-oriented models.
本文引入面向对象的时空数据模型，把各种实体作为对象，把道路作为面状要素描述。
The paper introduced object oriented spatiotemporal data model, looked on all kinds of things as objects and described road as face shape element.
本文引入面向对象的时空数据模型，把各种实体作为对象，把道路作为面状要素描述。
The paper introduced object oriented spatiotemporal data model, looked on all kinds of things as objects and described road as face shape element.
应用推荐