Succeeding with Object Databases: A Practical Look at Today's Implementations with Java and XML

468 Pages·2000·9.36 MB·English

by  Akmal B. Chaudhri

Succeeding with Object
Databases
A Practical Look at Today's
Implementations with Java™
and XML
Akmal B. Chaudhri
Roberto Zicari
Publisher: Robert Ipsen
Editor: Theresa Hudson
Developmental Editor: Kathryn A. Malm
Managing Editor: Angela Smith
Text Design & Composition: Benchmark Productions, Inc.
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This book is printed on acid-free paper. ©
Copyright © 2001 by Akmal B. Chaudhri and Roberto Zicari. All rights reserved.
Published by John Wiley & Sons, Inc.
Published simultaneously in Canada.
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Library of Congress Cataloging-in-Publication Data:
Chaudhri, Akmal B.
Succeeding with Object databases : a practical look at today's implementations
with Java and XML / Akmal B. Chaudhri, Roberto Zicari
p. cm.
Includes bibliographical references and index.
ISBN 0-471-38384-8 (cloth : alk. paper)
1. Object-oriented databases. 2. Java (Computer program language) 3. XML
(Document markup language) I. Zicari, Roberto. II. Title.
QA76.9.D3 C3848 2000
005.75'7-dc21 00-043455
Printed in the United States of America.
10 9 8 7 6 5 4 3 21
Per Aldo.
-RZ

Contents
Acknowledgments xiii
Introduction XV
Part One: Introduction 1
Chapter 1 OODBMS History and Concepts 3
Historical Perspective 4
The Beginning 4
Standardization 5
Object-Relational DBMSs 6
Java 8
OODBMS Products and Their Evolution 9
ORION/Itasca 9
O2 10
GemStone 11
IRIS/OpenODB 11
Vbase/Ontos 12
ObjectStore 12
POET 13
Data Model Concepts 13
Objects 13
Classes 16
Inheritance 19
An Example 21
Query Language 23
Conclusion 25
Part Two: Object-Relational Systems 27
Chapter 2 Mapping UML Diagrams to Object-Relational
Schemas in Oracle 8 29
Overview of UML 31
Overview of Oracle 8 35
Mapping Issues 37
vi Contents
Objects and Relationships between Objects 38
Object Hierarchies 39
VARRAYS and Nested Tables 42
Triggers for Maintaining Inverses 44
Derived Attributes 45
Embedded Objects 46
Queries over Objects 48
Comparison to Other Systems 48
Conclusion 50
Chapter 3 SQLJ and JDBC: Database Access in Java 53
A Bit of Background 53
SQLJ Basics 54
Embedded SQL Syntax 55
SQLJ Translator 55
Execution Model 56
The SQLJ Standard 56
JDBC Basics 57
Statements 57
A Note on Deployment 58
Connecting to the Database 58
Connecting at Run Time in SQLJ 59
Connecting to the Database
for SQLJ Translation 60
Connecting in JDBC 60
Mix and Match SQLJ and JDBC 60
Interfacing SQL and Java 61
Retrieving Data through an SQL Query 61
Datatype Mapping 66
Performance, Performance 69
JDBC Prepared Statements 69
Batching of Updates 70
Connection Pooling 70
SQLJ and JDBC in Oracle 8i 71
SQLJ versus JDBC 72
Conclusion 72
Chapter 4 Penguin: Objects for Programs, Relations for Persistence 75
Mapping from the Object Model to the Relational Model 76
Relational Database Storage and Semantic Modeling 79
Defining Object Views of Relational Databases 79
Updating Base Relations from Objects 81
Heterogeneous Data Sources 81
Methods 82
Concurrency Control 83
Contents vii
Performance Issues 83
Caching Structure 83
Cache Management 84
Data Transfer 86
Future Directions 87
Conclusion 87
Part Three: XML 89
Chapter 5 A New Stage in ODBMS Normalization: Myth or Reality? 91
State of the ODBMS Market 91
Why a Standard Like ODMG? 93
ODMG; A Reconciliation between Programming
Languages and DBMSs 95
An RDBMS Evolution toward Object Paradigm 96
XML Application Founded on OQL 97
System Motivations 98
Why XML? 98
The Database Model 100
Database Management Using O2 versus Versant 101
The Information Retrieval Technique 103
Conclusion 106
Chapter 6 PDOM: Lightweight Persistency Support 107
Introduction to DOM 108
Architecture 108
Binary File Organization 109
Persistent Object Manager 111
Object Serialization and Deserialization 111
Cache Strategy 112
Safe File Updates 113
Performance Evaluation 116
Related Work 116
Conclusion 118
Chapter 7 The Model of Object Primitives (MOP) 119
Model of Object Primitives 121
MOP Semantics 121
MOPClass 121
Constraint 123
State Class 123
Behavior Class 124
Policy 125
Collection Class 127
viii Contents
Relationship 127
Mapping Data Models to MOP 129
XML in MOP 129
ODMG in MOP 133
Relational Model in MOP 137
Case Studies 139
Conclusion 142
Part Four: Benchmarks and Performance 145
Chapter 8 A Performance Comparison of Object and
Relational Databases for Complex Objects 147
The Application 148
The OO Model 148
The EER Model 149
One Complex Object 149
Database Operations 150
Open and Close the Database 152
Pick Top Objects 152
Traverse Complex Objects 153
Copy Complex Objects 153
Inserts of Complex Objects 153
154
Deletes of Complex Objects
155
Updates of Complex Objects
Benchmark Considerations 155
The DBMSs Used 155
Test Environment 155
Warm and Cold Runs 156
Database Considerations 157
Benchmarks Results 157
Database Sizes 157
Open and Close the Databases 157
Pick Top Objects 159
Traverse Complex Objects 159
Copy Complex Objects 160
Inserts of Complex Objects
162
Deletes of Complex Objects
163
Updates of Complex Objects
165
Conclusion
166
Chapter 9 Object Databases and Java Architectural Issues 167
ODBMS Architecture 167
Object, Page, and File Servers 168
Performance Issues 168
Java Language Binding 176