一个面向对象的实体-联系-时间模型

An Objected-Oriented Entity- Relation-Time Model

讨论了一种应用于时态数据库的数据模型———面向对象的实体 联系 时间 (ERT)模型 .将时态概念作为模型组成部件 ,重点描述了其模型结构和重要的时态概念 ,简要介绍了相应的时态关系代数操作 。

An entity relation time model is introduced, which is a new objected oriented data model supporting time expression applied in temporal database. In the ERT model, the concept of temporal is used as an important component. On the basis of ER model, the ERT model is expanded a great amount of features for the modeling of the temporal applications. The ERT model structure and the important temporal concepts are primarily described, and the temporal relation algebra and the corresponding constrains introduced briefly.