Book Image

OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide

Book Image

OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide

Overview of this book

Oracle Database Server is the most widely used relational database in the world today. This book gives you the essential skills to master the fundamentals of Oracle database administration and prepares you for Oracle DBA certification."OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide" prepares you to master the fundamentals of Oracle database administration using an example driven method that is easy to understand. The real world examples will prepare you to face the daily challenges of being a database administrator.Starting with the essentials of why databases are important in today's information technology world and how they work, you are then guided through a full, customized installation of the Oracle software and creating your own personal database. We then examine fundamental concepts of Oracle, including architecture, storage structures, security, performance tuning, networking, and instance management. Finally, we take an in-depth look at some of the most important concepts in the daily life of an Oracle DBA - backup, recovery, and data migration."OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide" provides you with the skills you need in order to become a successful Oracle DBA, both for certification and real life tasks.
Table of Contents (24 chapters)
OCA Oracle Database 11g: Database Administration I: A Real-World Certification Guide
Credits
Foreword
About the Author
About the Reviewer
www.packtpub.com
Preface
Index

Managing serialization mechanisms


The concurrency mechanisms that we explored thus far involve mainly maintaining multiple versions of a block and displaying the correct version of a given block to a user. There are, however, other mechanisms that serialize access to table rows, database objects, or other system resources. As an RDBMS cannot allow two users to operate on the same piece of data at exactly the same time, it must have rules in place that prevent such an occurrence. As a simple example, imagine a four-way traffic stop. As more than one automobile cannot cross the same space at the intersection at exactly the same time, control mechanisms such as a traffic light must be employed to prevent collisions. In a similar manner, Oracle uses locks, latches, and mutexes to serialize access to objects and resources.

Understanding Oracle's locking scheme

Oracle's locking rules are designed to facilitate proper row and object concurrency between users. This locking is handled by the Oracle...