This paper describes a language that is intended to support software engineers in the development of information systems throughout the software lifecycle. This language is not a programming language. Following the example of a number of other software engineering projects, our work is based on the premise that information system development is knowledge-intensive and that the primary responsibility of any language intended to support this task is to be able to formally represent the relevant knowledge.

this paper, I will survey a number of temporal formalisms and systems from Knowledge Representation and Databases. Work in these two areas is particularly relevant if one is interested in designing and implementing a Temporal Knowledge Base Management System (TKBMS). KBMSs have been recently proposed for the construction, maintenance and querying of large shared knowledge bases [BM86], [Ull88], [Ull89], [ST89]. Since so many practical problems involve temporal reasoning, it is an interesting reasearch problem to design and implement a TKBMS which can be used for storing and retrieving large amounts of knowledge about these problems. For example, a job-shop scheduling system like ISIS [FS84], [FM86] could take advantage of a TKBMS for storing knowledge about orders, products, resources and schedules. This knowledge could be shared between schedulers and plant staff. A TKBMS would also be useful as a component of a medical information system used for recording and analyzing symptoms, diseases and their effects on patients over time [WBW86]. To keep the rest of the discussion in perspective, I will now present a number of requirements which must be met by a TKBMS