Cover: Interrogating a Relational Data File

Interrogating a Relational Data File

Remarks on the Admissibility of Input Queries

Published 1970

by J. L. Kuhns


Download eBook for Free

FormatFile SizeNotes
PDF file 1.8 MB

Use Adobe Acrobat Reader version 10 or higher for the best experience.


Purchase Print Copy

 Format Price
Add to Cart Paperback59 pages $20.00

This report continues the work, begun in RM-5428, of developing and implementing a theory of data retrieval for a computerized question-answering system in which the queries are represented as formulas of the predicate calculus and the database consists of atomic sentences. Algorithms for processing queries involving a full vocabulary of binary operators are given. It is shown that definite formulas having at most two levels of operators from certain minimal operator sets can always be transformed into proper formulas (i.e., formulas consisting entirely of definite subformulas) and algorithms for these "admissibility" transformations are given. In addition to the conventional operators, a new form of universal quantification is proposed for query systems. Rules for evaluation are given, and it is shown that the class of definite formulas is closed under this new "generalized universal quantification." Finally, theoretical limitations on methods of determining propriety through admissibility transformations are discussed.

This report is part of the RAND report series. The report was a product of RAND from 1948 to 1993 that represented the principal publication documenting and transmitting RAND's major research findings and final research.

This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited; linking directly to this product page is encouraged. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial purposes. For information on reprint and reuse permissions, please visit

RAND is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.