Object-Relational Database Development : A Plumber's Guide / Edition 1

Preface

New technologies are useful to the extent that they enhance some human ability. Simple machines like levers, pulleys, and inclined planes are useful because they make us stronger: that is, they increase the amount of mass that an individual can lift. Information technology—computer hardware and the software running on it—makes us smarter by enhancing our abilities to remember, reason, and communicate.

Computer hardware and software enhances mental abilities because they do the following things extremely well.

• Store information. Computers can record enormous amounts of data, far more than a single person can remember. And a computer's powers of recall are quicker and more accurate than our own.
• Process information. Computers can make a tremendous number of simple deductions quickly and without mistakes. This allows them to process large amounts of raw data to create new knowledge: to produce an analytic summary or to extract a subset of information from it.
• Communicate. Computer networks are very efficient at making information available to widely distributed community of user. And computers can be used to create flexible, intuitive interfaces, helping users comprehend and manipulate information.

These properties account for the way computer systems, and particularly information management systems, have become an indispensable part of modern corporate life. In today's knowledge-based economy, companies are organized into networks of cooperating employees. Each interconnected employee's work assignment is a subtask of what the company as a whole is trying to accomplish. What tiesemployees together is the information they share. So coordinating employee efforts requires an effective and efficient information management system.

Taking this idea one step further, it is becoming increasingly common to consider your customers and partners as part of the network too. Over the next few years economic transactions between businesses will increasingly be handed electronically. Achieving this requires that businesses make internal information systems available to outside agencies.

The intent of this book is to describe a new information management technology, Object-Relational Database Management Systems software, and explain how to use it. Although most DBMS vendors lay claim to selling object-relational databases, Informix's Dynamic Server product possesses the most complete set of features combined with exceptional performance, scalability, and reliability.

Most readers will come to this book with a familiarity with Informix's earlier products. Some may be anxious about the changes the new technology brings, but hopefully, this book will convince them that everything they know is still valid and useful. For other readers, this will be their first exposure to both INFORMIX and to extensible DBMS technology. Many of these readers will be building information systems that make specific use of the new features.

At this time, most of the features and functionality described in this book are scheduled for inclusion in all mainstream DBMS products. Implementation details vary, but the idea that a database's data model can include more semantic information than is captured with a VARCHAR() has become mainstream. It is enshrined in the SQL-3 standard, and as we shall see it is supported by several open language standards.