Oracle Distributed Systems

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 Considerations

Part 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: Appendixes Appendix A: Built-in Packages for Distributed Systems Appendix B: Scripts