Query Languages in Data Base Systems

Abstract

This is a considerably shortened version of a survey on query languages /1/ on the background of the users and applications they are designed to serve and the data models and data base systems on which they operate. The query languages discussed include also restricted natural language interfaces to data base systems, as research in this direction has been very active in recent years. A classification of each query language is given after a discussion of functional and user oriented requirements. Results on the evaluation of query languages are presented. The conclusions are drawn (1) that there does not exist a theory of query languages yet, which implies that criteria for comparing them must be more thoroughly defined, and (2) that, since most query languages were designed for non-programmers, more research is required to determine what these users need and to what extent existent or future query languages satisfy these needs. All references can be found in /1/.