Combi C, Pinciroli F, Pozzi G
Dipartimento di Bioingegneria del Politecnico di Milano, Italy.
Methods Inf Med. 1995 Dec;34(5):458-74.
In the field of databases, time management at different levels of granularity has been an issue for several years, for instance when dealing with clinical information from different databases using different time units, dealing with natural language expressions, or when dealing with temporal uncertainty. A temporal data model is proposed to manage the temporal aspect of data, presented at various and mixed levels of granularity. The concept of temporal assertions shapes the entire temporal information. The model provides a temporal dimension to the data by using intervals that can be specified at different granularities. The model supports a three-valued logic, where True, False and Undefined are the truth values. The temporal data model allows to manage some degrees of uncertainty when establishing temporal relationships between intervals or between temporal assertions, expressed at different granularities. The logical connectives and quantifiers can manage each of the three truth-values. We applied the temporal data model by implementing an object-oriented database system for managing follow-up clinical data from patients who underwent percutaneous transluminal coronary angioplasty.
在数据库领域，不同粒度级别的时间管理多年来一直是个问题，例如在处理来自不同数据库、使用不同时间单位的临床信息时，处理自然语言表达式时，或者处理时间不确定性时。提出了一种时态数据模型来管理数据的时间方面，该模型以各种混合粒度级别呈现。时态断言的概念塑造了整个时态信息。该模型通过使用可以在不同粒度级别指定的时间间隔为数据提供了一个时间维度。该模型支持三值逻辑，其中真、假和未定义是真值。时态数据模型在建立不同粒度级别表示的时间间隔之间或时态断言之间的时间关系时允许管理一定程度的不确定性。逻辑连接词和量词可以处理这三个真值中的每一个。我们通过实现一个面向对象的数据库系统来应用时态数据模型，该系统用于管理接受经皮腔内冠状动脉成形术患者的随访临床数据。
