Sakti P. Ghosh

EXPRESS: a data EXtraction, Processing, and Restructuring System

EXPRESS is an experimental prototype data translation system which can access a wide variety of data and restructure it for new uses. The system is driven by two very high level nonprocedural languages: DEFINE for data description and CONVERT for data restructuring. Program generation and cooperating process techniques are used to achieve efficient operation. This paper describes the design and implementation of EXPRESS. DEFINE and CONVERT are summarized and the implementation architecture presented. The DEFINE description is compiled into a customized PL/1 program for accessing source data. The restructuring specified in CONVERT is compiled into a set of customized PL/1 procedures to derive multiple target files from multiple input files. Job steps and job control statements are generated automatically. During execution, the generated procedures run under control of a process supervisor, which coordinates buffer management and handles file allocation, deallocation, and all input/output requests. The architecture of EXPRESS allows efficiency in execution by avoiding unnecessary secondary storage references while at the same time allowing the individual procedures to be independent of each other. Its modular structure permits the system to be extended or transferred to another environment easily.

File organization: the consecutive retrieval property

The consecutive retrieval property is an important relation between a query set and record set. Its existence enables the design of an information retrieval system with a minimal search time and no redundant storage. Some important theorems on the consecutive retrieval property are proved in this paper. Conditions under which the consecutive retrieval property exists and remain invariant have been established. An outline for designing an information retrieval system based on the consecutive retrieval property is also discussed.

Statistical relational tables for statistical database management

E.F. Codds (1970) relational view is extended to represent statistical data and to achieve its analysis. A new view called a statistical relational table is presented to meet the needs of statisticians, and some of Codds relational operators are extended to statistical relational tables. New operators based on these tables are introduced for communicating requests for statistical analysis. A new query language called the query-by-statistical-relational-table (which has some similarities to query-by-example) is introduced. Extensions of the SQL language for processing the commands of the new query language are also discussed. Creation and storage of metadata for fast statistical analysis are considered. Some problems related to privacy in statistical databases are also examined.

File organization schemes based on finite geometries

Some new schemes, possessing certain desirable properties, for organizing records with binary-valued attributes have been defined. It has been shown that it is possible to construct these filing schemes using finite geometires. The search time for a query involving any k attributes for these filing schemes based on finite geometries is very small in comparison wih existing filing schemes. Moreover, the search time does not depend on the number of records. The problem of updating is also quite simple.

Consecutive storage of relevant records with redundancy

This paper studies the properties of a new class of file organizations (CRWR) where records relevant to every query are stored in consecutive storage locations but the organizations contain redundancy. Some theorems which provide tools for reducing redundancy in CRWR organizations have been also developed. Redundancies obtained by the application of these theorems are compared with that of query-inverted file organizations. Some CRWR organizations with minimum redundancy have also been developed for queries which specify sets of keys.

On the theory of consecutive storage of relevant records

Abstract A set of queries is said to have the consecutive retrieval property w.r.t. a set of records if all the records pertinent to any query belonging to the query set can be stored in consecutive storage locations. Some theorems have been established for query sets and record sets which have (or have not) the consecutive retrieval property. It has been shown that the set of all binary queries do not have the consecutive retrieval property w.r.t. the set of all binary records. The importance of nested queries in this context has been discussed.

1978 New Orleans Data Base Design Workshop Report

This is a summary of a bigger report based on the results arrived at the New Orleans data base design workshop. This paper outlines the four major areas of data base design. It discusses the important issues, some of the results which have been achieved and future research problems.

Distributing a Data Base with Logical Associations on a Computer Network for Parallel Searching

The problem of distributing a data base (with logical associations between segment types) on a computer network such that multiple segment types satisfying a query can be retrieved in paralel from different nodes has been introduced. Properties of such distributions without redundancy and with redundancy have been discussed. Lower bounds on the number of nodes needed for such distributions have been given. Algorithms for constructing such distributions have also been given. Distributions of data bases for queries whose target segments form a combinatorial set have been studied in detail. Closed form expressions for redundancy have been obtained for such query sets.

File Organization: On the Selection of Random Access Index Points for Sequential Files

The construction of a hierarchy of indexes (the indexed sequential access method) is one means of providing rapid random access to sequential files. An examination is made of the consequences of partially or completely replacing one or more index levels by linear interpolation procedures. For all possible configurations of the several types of key distributions investigated, linear interpolation on the average provides significant performance improvements. Typically, the two accesses required to obtain track index and data are reduced to 1.1 to 1.7 accesses per record. Extremely unusual key distribution will, however, raise the number of accesses required above 2.

Quest: a project on database mining

Several organizations have collected massive amounts of data. These data sets are usually stored on tertiary storage and are very slowly migrating to database systems. One of the reasons for the limited success of database systems in this area is that current database systems do not provide the necessary functionality for a user interested in taking advantage of this information. Database mining refers to the efficient construction and verification of models of patterns embedded in large databases, and is emerging as a major application area for databases. The goal of the Quest project is to enhance database technology to address this problem.