This paper describes alternative methods for data access that are available to developers using the Java™ platform and related technologies to create a new generation of enterprise applications. The paper highlights industry trends and describes Java technologies that are responsible for a new paradigm in data access. Java technology represents a new level of portability, scalability, and ease-of-use for applications that require data access.

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Performance is a major issue in the acceptance of object-oriented and relational database systems aimed at engineering applications such as computer-aided software engineering (CASE) and computer-aided design (CAD). Because traditional database systems benchmarks are inapproriate to measure performance for operations on engineering objects, we designed a new benchmark Object Operations version 1 (OO1) to focus on important characteristics of these applications. OO1 is descended from an earlier benchmark for simple database operations and is based on several years experience with that benchmark. In this paper we describe the OO1 benchmark and results we obtained running it on a variety of database systems. We provide a careful specification of the benchmark, show how it can be implemented on database systems, and present evidence that more than an order of magnitude difference in performance can result from a DBMS implementation quite different from current products; minimizing overhead per database call, offloading database server functionality to workstations, taking advantage of large main memories, and using link-based methods.

There are two widely-known benchmarks for database management systems the TP1 benchmarks (Anon et al [1985]), designed to measure transaction throughout, and the Wisconsin benchmarks (Bitton, Dewitt, & Turbyfil [1984]), designed to measure the performance of a relational query processor. In our work with databases on engineering workstations, we found neither of these benchmarks a suitable measure for our applications' needs. Instead, our requirements are for response time for simple queries. We propose benchmark measurements to measure response time, specifically designed for the simple, object-oriented queries that engineering database applications perform. We report results from running this benchmark against some database systems we use ourselves, and provide enough detail for others to reproduce the benchmark measurements on other relational, object-oriented, or specialized database systems. We discuss a number of factors that make an order of magnitude improvement in benchmark performance caching the entire database in main memory, avoiding query optimization overhead, using physical links for prejoins, and using an alternative to the generally-accepted database “server” architecture on distributed networks.

A study is presented of a database system interface in which an entity (a concept) and the relationships in which it is involved are displayed to the user: the user is permitted to move about in the database by selecting entities related to the current one displayed. The database system is intended as a personalized database (PDB) for a scientist, student, manager, or anyone who has a need for a fast mechanism for storing and organizing a wide variety of information. The study is exploratory recording baseline times and types of behavior for a variety of personal information management tasks performed by one individual. Data entry, information retrieval, and browsing behavior are examined and contrasted to behavior with more conventional storage media.

The Cedar DBMS is a database management system developed as part of the Cedar programming environment. The system has several unusual aspects, including its interface for applications programming in a strongly-typed procedural language and its distribution of computation and data over a network. This paper describes the design goals, architecture, and implementation of the Cedar DBMS.

A user interface to a database designed for casual, interactive use is presented. The interface is entity-based: the data display to the user is based upon entities (e.g., persons, documents, organizations) that participate in relationships, rather than upon relations alone as in the relational data model. Examples from an implementation of the system are shown, for a prototype personal database (PDB), developed in connection with the ZOG system at Carnegie-Mellon University (Robertson et al[1977]). Some details of the interface and associated issues concerning data display, data models, views, and knowledge-based assistance are presented. Experience with the prototype system suggests that the entity-based presentation is appropriate for types of casual interactive use that existing database interfaces do not address, such as browsing. It is proposed that such an interface could be used to supplement a query language or other interface to allow users both kinds of views of the data.

Work with compiler compilers has dealt principally with automatic generation of parsers and lexical analyzers. Until recently, little work has been done on formalizing and generating the back end of a compiler, particularly an optimizing compiler. This paper describes formalizations of machines and code generators and describes a scheme for the automatic derivation of code generators from machine descriptions. It was possible to separate all machine dependence from the code generation algorithms for a wide range of typical architectures (IBM-360, PDP-11, PDP-10, Intel 8080) while retaining good code quality. Heuristic search methods from work in artificial intelligence were found to be both fast and general enough for use in generation of code generators with the machine representation proposed. A scheme is proposed to perform as much analysis as possible at code generator generation time, resulting in a fast pattern-matching code generator. The algorithms and representations were implemented to test their practicality in use.