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| Preface |

## About PL/Vision

PL/Vision is a collection of PL/SQL packages and supporting SQL*Plus scripts which can radically change the way you develop applications with the PL/SQL language. PL/Vision programs can be put to work instantly in your environment, as standalone utilities, low-level functions, and plug-and-play components. You can retrofit existing applications to use PL/Vision or simply apply it to new development. Part 2, PL/Vision Overview of this book explains PL/Vision in detail -- what it consists of and how to use it.

PL/Vision is offered in two "flavors" by RevealNet, Inc.: Lite and Professional. PL/Vision Lite is the version of PL/Vision which serves as a companion product to this book. It was developed to help you take advantage of many advanced PL/SQL techniques in your own development environment. While PL/Vision Lite's functionality will not be extended, I will provide fixes to any bugs reported in that version of PL/Vision since the release of this book. You can check out the most current version of PL/Vision Lite on RevealNet's site at http://www.revealnet.com. Chapter 4 describes how to install the PL/Vision Lite software.

PL/Vision Professional is a fully supported and constantly evolving product. It offers a wider range of functionality, comprehensive leveraging of the latest versions of PL/SQL (including PL/SQL Release 2.3, Oracle Web Agent extensions, and PL/SQL Version 3, which will support object technology in the Oracle8 Server), and many code samples to help you take full advantage of PL/Vision. You can register for -- or simply get more information about -- PL/Vision Professional at the http://www.revealnet.com Web site.

I like to think of PL/Vision as more than just a software product; it is an open channel of communication between me and PL/SQL developers around the world. It is the means by which I will share my new discoveries in PL/SQL, especially those discoveries I can transform into packages for your use. It is also the way (through www.revealnet.com) for you to let me know about your suggestions for enhancements to PL/Vision.

PL/Vision is a large and complex body of code. This book and the PL/Vision Online Reference (on the companion disk) should go a long way towards making the software more accessible and useful to you. You can use this book both as user guide and mentor. You can use the Online Reference as a quick syntax checker for PL/Vision and also as a mechanism to view the source code of PL/Vision.

### Book as User Guide

One way to use this book is as a user's guide to PL/Vision Lite. Chapter 5 offers a quick reference view of all the different package specifications for the software. From these tables of program headers and package constants, you can quickly glean the syntax you need to follow to execute PL/Vision programs.

Each of the chapters in Parts III, IV, and V presents one or more of the PL/Vision packages. In these chapters I use a consistent format with the following elements:

- Introduction and overview.

- A guide to how to use the elements of the package.

- Special notes regarding the package (if any).

- An explanation of how the package was designed and built. This last section is present only for some of the packages and is explained more fully later, in .

To keep the length of the book reasonable, I do not reproduce the full specifications and bodies for the PL/Vision packages in the book, but I do highlight the most interesting aspects of the packages. I encourage you to use the editor of your choice or the PL/Vision Online Reference to examine the code at your leisure or in parallel with the reading of the book.

### Book as Mentor

I will be very happy if you decide to use PL/Vision in your development environment. More important than using PL/Vision, however, is learning how and why it is constructed the way it is. I will be happiest of all if, as a result of reading this book and studying my source code, you build your own version of PL/Vision: your own set of highly reusable, plug-and-play component packages.

I have tried to add content to the book itself that will move you along in this direction. In a number of the chapters, I go beyond describing how to use my packages to exploring why and how I build those packages. These implementation stories can go a long way in educating or inspiring you to build your own packages. In particular, see Chapter 8, PLVtab: Easy Access to PL/SQL Tables (PLVtab), Chapter 11, PLVobj: A Packaged Interface to ALL_OBJECTS (PLVobj), Chapter 15, PLVvu: Viewing Source Code and Compile Errors (PLVvu), Chapter 16, PLVgen: Generating PL/SQL Programs (PLVgen), Chapter 17, PLVhlp: Online Help for PL/SQL Programs (PLVhlp), Chapter 19, PLVdyn and PLVfk: Dynamic SQL and PL/SQL (PLVdyn), Chapter 20, PLVcmt and PLVrb: Commit and Rollback Processing (PLVcmt and PLVrb), and Chapter 22, Exception Handling (PLVexc). You will also find many smaller sections in other chapters offering insights into particular aspects of the packages.

### Online Information

Information related to this book and PL/Vision Lite is available on the World Wide Web at:

http://www.revealnet.com/plvision

> NOTE: Please check the Web site for any code changes to PL/Vision Lite which may have occurred since publication of this book.

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