Résumé
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).
This book describes how you can use multiple databases and the distributed features of Oracle to best advantage. Distributed databases environments offer a number of benefits over single-database systems, including:
- Tunability
- Platform autonomy
- Fault tolerance
- Scalability
- Location transparency
- Site autonomy
- Enhanced security
This book describes the benefits and tradeoffs of distributed database systems:
Part I presents background information on the uses of distributed databases, the configuration of SQL*Net (or Net8 for Oracle8) configuration and administration of the distributed environment, the special security considerations for distributed systems, and the design characteristics of distributed systems in general, and Oracle's in particular.
Part II describes the details of Oracle's distributed database features -- advanced replication, snapshots, multi-master replication, updateable snapshots, procedural replication, and conflict resolution.
Part III contains two appendixes. Appendix A is the API reference for all of the Oracle built-in packages used for distributed systems. Appendix B contains listing of the scripts provided with the book. These scripts are also included on the diskette that accompanies the book.
Table of contents
- Preface
- I. The Distributed System
-
- 1. Introduction to Distributed Systems
- Terminology and Concepts
- What Is a Distributed Database System?
- Benefits of Distributed Databases
- Multiple Schema Versus Multiple Databases
- Options for Distributed Data
- Perils of Distributed Databases
- Differences Between Oracle7 and Oracle8
- 2. SQL*Net and Net8
- Protocol Overview
- Architecture
- SQL*Net/Net8 Tuning
- Load Balancing
- Oracle8 Scalability Options
- SQL*Net/Net8 Client Configuration
- SNMP Support
- Security
- 3. Configuration and Administration
- Initialization Parameters
- Database Links
- Distributed Queries and Transactions
- Distributed Backup and Recovery
- Multiversion Interoperability
- 4. Distributed Database Security
- Privilege Management
- Authentication Methods
- 5. Designing a Distributed System
- Characteristics of a Distributed System
- The Global Data Dictionary
- Replication-Specific Issues
- Data Partitioning Methodologies
- Application Partitioning Strategies
- Procedural Replication
- 6. Oracle's Distributed System Implementation
- Meeting the 12 Objectives with Oracle
- Oracle's Global Data Dictionary
- 7. Sample Configurations
- The High-Availability System
- Geographic Data Distribution
- Workflow Partitioning
- Data Collection and Consolidation
- Loosely Coupled Federation
- 8. Engineering Considerations
- Schema Design and Integration
- Application Tiering
- Designing a Replicated System
- II. Replication
-
- 9. Oracle Replication Architecture
- What Is Oracle Replication?
- Types of Replication
- Architecture Components
- Replication of DDL
- Oracle8 Enhancements
- Oracle8i Enhancements
- Alternatives to Replication
- 10. Advanced Replication Installation
- Initialization Parameters
- Redo Logs and Rollback Segments
- Size and Placement of Data Dictionary Objects
- Administrative Accounts, Privileges, and Database Links
- 11. Basic Replication
- About Read-Only Snapshots
- Prerequisites and Restrictions
- Snapshot Creation Basics
- Simple Versus Complex Snapshots
- Snapshot Logs
- Subquery Subsetting
- Refresh Groups
- Management and Optimization
- Scripts
- 12. Multi-Master Replication
- Concepts and Terminology
- Getting Started
- Replication Groups
- Master Site Maintenance and Propagation
- Controlling Propagation
- The Replication Catalog
- Table Replication
- Replicating DDL
- Your Replicated Environment
- Advanced Replication Limitations
- 13. Updateable Snapshots
- About Updateable Snapshots
- Creating Updateable Snapshots
- Communication Flow
- Controlling Propagation and Refreshes
- Maintenance
- 14. Procedural Replication
- When to Use Procedural Replication
- How Procedural Replication Works
- Creating a Replicated Package Procedure
- Restrictions on Procedural Replication
- An Example
- 15. Conflict Avoidance and Resolution Techniques
- Data Integrity Versus Data Convergence
- Applications That Avoid Conflicts
- Types of Conflicts Detected
- How Oracle Detects and Resolves Conflicts
- Column Groups and Priority Groups
- The Built-in Methods
- Writing Your Own Conflict Resolution Handler
- III. Appendixes
-
- A. Built-in Packages for Distributed
Systems
- B. Scripts and Utilities
- A. Built-in Packages for Distributed
Systems
Caractéristiques techniques
| PAPIER | |
| Éditeur(s) | O'Reilly |
| Auteur(s) | Charles Dye |
| Parution | 23/04/1999 |
| Nb. de pages | 550 |
| Format | 17,8 x 23,2 |
| EAN13 | 9781565924321 |
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