Section I. Introduction to Query Processing.- to Query Processing.- Section II. Query Processing in Distributed Database Management Systems.- Query Processing in R.- Distributed Database Query Processing.- Processing Cyclic Queries.- Section III. Query Processing for Multiple Data Models.- Query Processing in a Multidatabase System.- Querying Relational Views of Networks.- Section IV. Database Updates through Views.- Updating Relational Views.- Section V. Database Access for Special Applications.- Supporting Complex Objects in a Relational System for Engineering Databases.- Database Access Requirements of Knowledge-Based Systems.- A Query Language for Statistical Databases.- Section VI. Techniques for Optimizing the Processing of Multiple Queries.- Common Subexpression Isolation in Multiple Query Optimization.- Global Optimization of Relational Queries: A First Step.- Query Processing Using the Consecutive Retrieval Property.- Section VII. Query Processing in Database Machines.- The Intelligent Database Machine (IDM).- Relational Query Processing on the NON-VON Supercomputer.- Section VIII. Physical Database Design.- Progress Toward Automating the Development of Database System Software.- Physical Database Design: Techniques for Improved Database Performance.- The Property of Separability and Its Application to Physical Database Design.- References.- List of Authors.

This book is an anthology of the results of research and development in database query processing during the past decade. The relational model of data provided tremendous impetus for research into query processing. Since a relational query does not specify access paths to the stored data, the database management system (DBMS) must provide an intelligent query-processing subsystem which will evaluate a number of potentially efficient strategies for processing the query and select the one that optimizes a given performance measure. The degree of sophistication of this subsystem, often called the optimizer, critically affects the performance of the DBMS. Research into query processing thus started has taken off in several directions during the past decade. The emergence of research into distributed databases has enormously complicated the tasks of the optimizer. In a distributed environment, the database may be partitioned into horizontal or vertical fragments of relations. Replicas of the fragments may be stored in different sites of a network and even migrate to other sites. The measure of performance of a query in a distributed system must include the communication cost between sites. To minimize communication costs for-queries involving multiple relations across multiple sites, optimizers may also have to consider semi-join techniques.