This is a unique, one-volume guide to the administration and management of the Oracle database. Fully revised and updated from its best-selling 9i predecessor, this edition covers all new features, with fully field-tested examples-not just “showcase” examples.
This book covers the new 10g management and performance tools and provides essential primers on Unix, Linux and Windows NT administration and on core SQL and PL/SQL programming techniques. And it provides everything the new and aspring Oracle DBA needs to build and admisiter complex Oracle 10g databases.
In the first three chapters, I set the stage for working with Oracle. It’s time now to learn about the fundamental structures of Oracle Database 10g. Oracle uses a set of logical structures called data blocks, extents, segments, and tablespaces as its building blocks. Oracle’s physical database structure consists of data files and related files. Oracle memory structures and a set of database processes constitute the Oracle instance, and are responsible for actually performing all the work for you in the database.
To understand how the Oracle database works, you need to understand several concepts, including transaction processing, backup and recovery, undo and redo data, the optimization of SQL queries, and the importance of the data dictionary. Oracle’s key features include the Recovery Manager, SQL*Plus and iSQL*Plus, Oracle Backup, the Oracle (job) Scheduler feature, the Database Resource Manager, and the Oracle Enterprise Manager management tool. This chapter provides an outline of the important Oracle automatic management features, as well as the sophisticated built-in performance tuning features, including the new Automatic Workload Repository, the Automatic Database Diagnostic Monitor, and the advisor-based Management Framework.
Before you delve deeply into the logical and physical structures that make up an Oracle database, however, you need to be clear about a fundamental concept-the difference between an Oracle instance and an Oracle database. It is very common for people to use the terms interchangeably, but they refer to different things altogether.
An Oracle database consists of files, both data files and Oracle system files. These files by themselves are useless unless you can interact with them somehow, and this requires the help of the operating system, which provides processing capabilities and resources, such as memory, to enable you to manipulate the data on the disk drives. When you combine the specific set of processes created by Oracle on the server with the memory allocated to it by the operating system, you get the Oracle instance.
You’ll often hear people remarking that the “database is up,” though what they really mean is that the “instance is up.” The database itself, in the form of the set of physical files it’s composed of, is of no use if the instance is not up and running. The instance performs all the necessary work for the database.
