Knowledge bases constitute the core of those Artificial Intelligence
programs which have come to be known as Expert Systems. An
examination of the most dominant knowledge representation schemes used
in these systems reveals that a knowledge base can, and possibly
should, be described at several levels using different schemes,
including those traditionally used in operational databases. This
chapter provides evidence that solutions to the organization and
access problem for very large knowledge bases require the employment
of appropriate database management methods, at least for the lowest
level of description -- the facts or data. We identify the database
access requirements of knowledge-based or expert systems and then
present four general architectural strategies for the design of expert
systems that interact with databases, together with specific
recommendations for their suitability in particular situations. An
implementation of the most advanced and ambitious of these strategies
is then discussed in some detail.Information Systems Working Papers Serie