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Access Independent Query Definition in IBM DL/I

IP.com Disclosure Number: IPCOM000062542D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09

Publishing Venue

IBM

Related People

Authors:
Larner, A [+details]

Abstract

An implementable mapping between DL/I data bases by means of a simple conceptualization of their structure associates together the set of paths defined in various data bases and having a common query structure; that is to say, any one of the set may be used to execute a query defined on any of the others. Membership of this set is both a necessary and a sufficient condition for access equivalence with any other member of the set and allows a query system the widest possible domain of effective paths from which its access optimization routines may select the most efficient. The definition of these domains, each associated with a segment selectable for a query, may efficiently be performed once only, before online query execution.