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PREFACE: The you in this book, whether the word is stated or implied, is the database administrator. Throughout, I assume that most of my readers are DBAs or other information-systems professionals who will work with the Oracle Server.
At the same time, this direct approach makes the book accessible and worthwhile to other readers, as well.
If you are a programmer, you will learn enough about the Server to write applications that take advantage of the Server's features, instead of duplicating those features in your code. Furthermore, because the book is organized around broad database topics--such as security, integrity, and consistency--rather than by product features, you will quickly see how the Oracle Server solves the classic database problems. People who are new to Oracle products but have worked with other database systems, or students of database theory, will benefit the most from this organizational scheme. But even if your previous experience has taught you almost nothing about databases--perhaps you're a computer hobbyist, a freelance technical writer, or prospective Oracle employee--you will come away from this book with a good understanding of what the Oracle Server is all about. While product features and functions change with great frequency, relational-database fundamentals remain the same. By grounding descriptions of the product in a broader theoretical framework, I try to offer you lasting value, a quality which--just by the nature of the industry--few software manuals or after-market books have.
Nonetheless, this book is not for everyone. Even though it's written simply, it does assume you have a certain level of computerliteracy. For example, you should understand such general terms and concepts as "operating system," "application," "memory," and "I/O." But, like me, you don't have to be a computer scientist to understand how the Oracle Server works.
The book is organized into two major sections. Part I (Chapters 1-4) introduces the subject and describes the architecture of the Server and of an Oracle database. Part II (starting with Chapter 5) describes classic database problems and major database administration tasks, and shows how the Oracle Server solves these problems.
Chapter 1 presents "the big picture," showing how the Oracle Server fits into the suite of Oracle products and into the client/server computing model.
Chapter 2 briefly explains the relational model and introduces its major components: the table, the column, and the row. It then describes the major features and commands of SQL, the language used to interact with the Oracle Server and to define and manipulate data in an Oracle database.
Chapter 3 describes how the Oracle Server organizes data. It describes various schema objects, tablespaces, the data dictionary, and other logical structures.
Chapter 4 discusses the physical file structure of an Oracle database, as well as the memory and process structures that the Oracle Server uses to manage data on behalf of users. It explains the importance of the SGA and the background processes, and explains how these structures work as part of the larger database management system.
Chapter 5 explains the major types of data integrity and shows how you can use the Oracle Server to create a database that conforms to various integrity rules. It describes the Oracle datatypes, integrity constraints, and programmatic methods of enforcing integrity rules.
Chapter 6 shows how the Oracle Server guarantees data consistency while allowing high concurrency. It describes the mechanics behind such features as row-level locking and multi-version read consistency.
Chapter 7 explains when to start up or shut down an Oracle instance and tells how to do so. It also describes some of the most important initialization parameters that you might set.
Chapter 8 gives guidelines for managing space usage, from the file level down to the block level. The aim is to strike a balance between high performance and efficient use of disk space.
Chapter 9 introduces the major ways to optimize performance. It discusses such topics as memory allocation and statistics-gathering, the query optimizer, and the use of indexes and hash clusters.
Chapter 10 describes the Oracle7 security features. It explains your options for identification and authentication, shows how to use privileges and roles, and introduces the Server's auditing features.
Chapter 11 explains how to protect your database against failure. It describes the types of failure, tells how to perform different types of backup, and explains how the Server performs recovery.
Chapter 12 describes the distributed processing capabilities of the Oracle Server. The chapter explains the creation and use of database links, the two-phase commit mechanism, and various replication options.
Chapter 13 introduces two major Oracle Server options which take advantage of multiprocessing computers. It explains the Parallel Server Option, which is designed for use on loosely coupled systems, and the Parallel Query Option, which can be used on any multiprocessing computer.
While Understanding the Oracle Server presents several advanced topics, it does so in ways that do not distract readers who only want to understand the basics. For example, many esoteric topics appear in sidebars, while the Server's advanced features and options are tucked away in the last two chapters. The main goal is to lay down a solid foundation for you to build on. If this book excites you about the capabilities of the Server and makes you comfortable enough with the subject to inspire you to explore further, my project will have been a success.