Mediating the views of databases and database users

The Natural-Language/Deduction group at SRI International has undertaken several large projects integrating knowledge representation, the modeling and use of distributed conventional databases, logical deduction, and natural-language processing. One of the largest projects, LADDER [2], involved accessing data distributed over a computer network by using queries expressed in English. Work with LADDER (and several similar systems) has revealed that: (1) Users wish to talk about data in terms of the enterprise in which the data are to be used. Users do not confine their questions to concepts and terminology covered by the database per se. (2) Users are seldom satisfied with access only to the data in a database. They need to know the KIND of data available (i.e., they want to ask questions about the DB schema), and they expect systems to include information that can be computed from “common knowledge” and information stored explicitly in the database (e.g., if a database records where two ships are, users expect the system to know the distance between them). (3) Users are not satisfied with access to an existing database. They want to tell the system new facts. Some of these are not suitable for storage in conventional databases (e.g., statements involving quantification), and some involve counter factuals (e.g., “Suppose the ship were 100 miles south of its current location...”). (4) Given natural-language access to a DBMS, users expect to interact in natural language with other types of software, too. Moreover, they expect the various underlying software packages to understand one another's results (e.g., User: “Who is the commander of the ship?” System: “Admiral Brown.” User: “Send him a copy of Smith's memo.” The mailer is expected to understand the output from the database).