Most databases store time-varying information. Existing database systems (e.g. relational database system) do not provide means to store and query such information in a direct way. The research area of temporal databases aims to provide a model of database system in order to manage time-varying data in an efficient and simple way. The paper concentrates on one of the aspects of databases, namely, a query language. The formal definition of a relational database model and one of the temporal database models are presented. Next, the definition of a query language for temporal database is shown. The language is a certain modification of the language of first order temporal logic which is an extension of the language of first order classical logic with new (temporal) connectives. These connectives enable to form queries about 'the course of events' in a natural, intuitive way. One does not need to use variables to refer to time, hence the transcript of a query is shorter and less complicated. A few of examples of queries, formed in the defined language, are presented at the end of the paper.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.