Any organization that uses the Oracle relational database management system (RDBMS) these days needs to use multiple databases. There are many reasons to use more than a single database in a distributed database system:
- Different databases may be associated with particular business functions, such as manufacturing or human resources.
- Databases may be aligned with geographical boundaries, such as a behemoth database at a headquarters site and smaller databases at regional offices.
- Two different databases may be required to access the same data in different ways, such as an order entry database whose transactions are aggregated and analyzed in a data warehouse.
- A busy Internet commerce site may create multiple copies of the same database to attain horizontal scalability.
- A copy of a production database may be created to serve as a development test bed.
In a distributed database environment, data in two or more databases is accessible as if it were in a single database. Usually, the different databases are on different servers, which may be located at the same site or a continent away. Communication between the servers takes place via SQL
Net (for Oracle7) or Net8 (for Oracle8).Distributed database environments offer a number of benefits over single- database systems, including:- Tunability
- Platform autonomy
- Fault tolerance
- Scalability
- Location transparency
- Site autonomy
This book describes how you can use multiple databases and the distributed features of Oracle to best advantage. It covers:Table of contents:Part I: The Distributed System- Introduction to Distributed Database Systems
- SQL
Net and Net8
Configuration and Administration Distributed Database Security Designing the Distributed System Oracle's Distributed System Implementation Sample Configurations 8. Engineering ConsiderationsPart II: Replication
- Oracle Replication Architecture
- Advanced Replication Option Installation
- Basic Replication
- Multi-Master Replication
- Updateable Snapshots
- Procedural Replication
- Conflict Avoidance and Resolution Techniques
Part III: AppendixesAppendix A: Built-in Packages for Distributed Systems Appendix B: Scripts
Charles Dye is the database architect for Excite, Inc. (www.excite.com), where he is responsible for the design and implementation of the databases theat supply content to some of the world's busiest Web sites. Prior to joining Excite, he was the senior database administrator for The Dialog Corporation. Charles also operates a small but growing consultancy with clients in the San Francisco Bay area and Hong Kong. Once upon a time, before fleeing the East Coast for California skies, Charles taught math and physics at the Georgetown Day School in Washington DC. Charles is a frequent speaker at regional and national Oracle events such as Oracle Open World and IOUG-A Live. His favorite topics are distributed databases in general and advanced replication in particular. He also writes for the Northern California Oracle Users Group newsletter and is an active contributor to the Oracle Internet list server. Look for Charles' upcoming O'Reilly book, Oracle Distributed Systems, available later in 1998. Charles lives in Los Altos, California, with his wife Kathy, daughter Natalie, and labrador Jed. You can email him at cdye@excite.com.
