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PREFACE: Preface
A database is the core, the center of an application, a very critical component of the application architecture. Vital application information flows in and out of this component. Failures or flaws in the database could have a severe impact on the entire application.
For this reason, because of this criticality, the correct administration of the database is of paramount importance. For an application to run without incident, the database used must operate correctly and efficiently. Smooth database operation requires not only proper administration, but a proper physical and logical design of the database, a design that should match the needs of the application using the database.
As an Informix database administrator, you must understand the full range of engine operations: from how the engine uses machine resources (CPU and disk), how data integrity is maintained through logging mechanisms, archive and recovery facilities, and most importantly, database monitoring and tuning. Starting with a discussion of basic terms and concepts and proceeding through a discussion of the engine architecture, this book covers each of these topics in turn.
As an Informix application developer, you must understand the operation of the database to correctly architect an application. Flexible data organization through static database fragmentation is a an important feature of the Informix database and if understood and used correctly, can improve performance for many applications. This book covers Informix fragmentation in detail, explaining how this important feature can be used to improve performance for data retrieval and ease dataadministration by placing portions of data in specific disk locations.
An Informix application developer or database administrator will interact with the Informix database using the Informix Structured Query Language (SQL). Understanding and using Informix-SQL wisely can save tremendous amounts of development and administration effort. The most commonly used Informix-SQL statements for both data manipulation and data definition are covered in this text complete with examples of usage.
One of the most enduring Fourth Generation Languages is Informix-4GL. This development language represents a well-conceived combination of procedural and non-procedural programming statements that allow a complete application to be developed with ease. This tool is excellent for the development of reports, database administration, and the transformation, conversion and filtering applications common in data warehouses and data marts. This language is covered in detail in this text.
Despite the common maxim, it is generally not the computer that fails but the human who programmed or administered it. Careful, knowledgeable design, programming and administration are the base upon which computer applications are built. These tasks require a solid knowledge foundation for the development tools being used. Using this book, you, the Informix developer or administrator, can develop that solid foundation of knowledge of the Informix product line for the products presented in this book.
Appreciation
Thanks to all those who helped in the development of this book. Thanks especially for the great home support: Carolyn, Hannah and Eric, and especially Carolyn. Their patience and understanding has been appreciated.
Thanks to all the technical editors including Harold Davis and Seth Grimes. Most significantly thanks to the technical editors Paul Gancz and Dave Kosenko who stayed with this effort to the end and whose keen technical expertise kept me on the straight and narrow.
Special thanks to the Informix Press member of this team, Judy Bowman whose help and efforts are greatly appreciated.
And finally, thanks to the production team at Prentice-Hall: Ralph Moore and Kerry Reardon who have helped make all this information clear, clean and presentable.