DATALOG is a natural language database query system which is under development at GM Research Laboratories. The objective is to produce a “portable” system, i.e., one which may be easily adapted for use with a variety of databases.

After a brief review of existing work in the field, the authors discuss (with examples) the implementation of syntactic analysis and semantic interpretation in DATALOG. They then describe the Application Lexicon, this being the place where the concepts, attributes, and values specific to a particular database are defined. In general, this lexicon will be redefined whenever DATALOG is to be used in a new application. Examples are given of the creation of two application lexicons. Finally, some areas for improvement of the system are discussed.

This is a well-written description of an interesting system. It is made much more comprehensible by the inclusion of well-chosen examples.