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ARPL - A RETRIEVAL PROCESS LANGUAGE

IP.com Disclosure Number: IPCOM000128816D
Original Publication Date: 1972-Aug-14
Included in the Prior Art Database: 2005-Sep-19
Document File: 13 page(s) / 41K

Publishing Venue

Software Patent Institute

Related People

Heindel, Lee E.: AUTHOR [+4]

Abstract

This article presents a description of ARPL - A Retrieval Process Language for hierarchical data bases. ARPL is a simple keyword oriented language built around the concept of a retrieval process on a hierarchical data base. The retrieval process allows one to delimit a hierarchical data base to a subset of the data base, apply logical tests on data in the data base, and compute the values of complex retrieval functions defined on data stored in the data base. ARPL will be seen to be a natural means of expressing the retrieval process in a nonprocedural language.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

ARPL - A RETRIEVAL PROCESS LANGUAGE

by Lee E. Heindel and Jerry T. Roberto

ARPL - A RETRIEVAL PROCESS LANGUAGE by Lee E. Heindel and Jerry T. Roberto
Room 2G-418
Bell Telephone Laboratories, Inc.

Holmdel, New Jersey 07733

ABSTRACT

This article presents a description of ARPL - A Retrieval Process Language for hierarchical data bases. ARPL is a simple keyword oriented language built around the concept of a retrieval process on a hierarchical data base. The retrieval process allows one to delimit a hierarchical data base to a subset of the data base, apply logical tests on data in the data base, and compute the values of complex retrieval functions defined on data stored in the data base. ARPL will be seen to be a natural means of expressing the retrieval process in a nonprocedural language.

Key Words and Phrases: programming languages, data bases, management information systems, query languages.

CR Categories: 4.29, 3.59, 3.74

1. Introduction

ARPL, A Retrieval Process Language is a keyword-oriented, nonprocedural language (see t63) which allows one to specify a complex retrieval process on a hierarchical data base. In specifying a retrieval process one can delimit a hierarchical data base to a subset of the data base, apply logical tests on data in the data base, and compute the values of complex retrieval functions. Such a retrieval process was first proposed and partially implemented by Sinowitz [ 5
] in a system called DATAPLUS. ARPL provides facilities to output the values of computed retrieval functions in several ways such as printing them in tabular form, point plotting them, or ranking them.

ARPL, being completely divorced of any file or record structure, can be implemented using any data base management system which can support logically hierarchical data bases. An example of such a system is the one proposed by the CODASYL Data Base Task Group t1,2,3,4 ]

1.1 Hierarchical Data Bases

A hierarchical data base is a directed tree which is rooted at one node. At each node in the tree is stored a set of variables. Two nodes belong to the same Group if the set of variables stored at one node is identical to the set of variables stored at the other. Two nodes belonging to the same group are at the same depth in the tree (de, connected to the root node of the tree by

Bell Laboratories Page 1 Aug 14, 1972

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ARPL - A RETRIEVAL PROCESS LANGUAGE

paths of the same length). Also the set of groups of nodes which are ancestors of one node belonging to a group must be identical to the set of groups of nodes which are ancestors of any other node belonging to the group.

Using the concept of groups, it is possible to represent the structure of a hierarchical data base as a rooted tree whose nodes are the groups of the hierarchical data base placed in the tree analogously to the nodes in the data base with respect to depth and connectivity. At each node in the group tree...